.\. •''% • . .i* ■J ■ ^^^^^^HC''' 1 ■ ^■KC 1..:^ ■.;,'.; :;-.:'f'., :„;/■ 1 ifi ^■i^^HHMiHBSto -7'*^-?-^'--^-'' ■ H^^HK^ V^;:-;^:::^ ' 7:: I H1HP^';-'^'';1 m ^HK^^HpdP^Mv"*^ "■'A'.- ■ -,--, ^' --"'■ -;"','^>-'':\ ■ -""'. ■ ;v''v^-Vi'--; ../ ■. *^/ '^v :-W.. .".N*:'.... ■' i:"^ .>/v- • >* -- f'--T-- >-, v^ ;^y-:i.:^^',*:-^ ;->. ' ■VV..-V ■■'■; v" -ir 1 ■k^^'^c' ■ ^^Hk*A^?_-^^ ■ B^v^^-' '".'^'1 ^/■''" v' ■ g;;- y.-rj "i?'" Nv* -■*. -^r ■ ^■H^^'*- -■''^ y^i^^. '^U^-v^ THE CAT OP THE LATTER TO THE EXTERNAL FORM. A / / ' THE CAT. AN INTRODUCTION TO THE STUDY OF BACKBONED ANIMALS ESPECIALLY MAMMALS By St. GEOEGE MIVAET, Ph.D., F.K.S. WITH 200 ILLUSTRATIONS. LONDON: JOHN MUEEAY, ALBEMAELE STEEET. 1881. [All Flights reserved.] LONDOK : BRADBURY, AONEW, & CO., rBlNTERS, WHITEFRTARS. foSS^ PREFACE. Biology is the science wliich treats of all living organisms, from Man to the lowest plant. Ko natm*al science is at present more keenly pursued or with more effect. The advances of Astronomy and Geology have produced great changes in men's minds during the last three centuries : Biology is producing changes at least as great, in the present age. So rapid has been its progress that the Natural History of Animals and Plants needs to be rewritten — the field of Nature being surveyed from a new stand-point. Such a history may be written in two ways : (1) Living beings may be treated as one whole, their various powers and the more general facts as to their organization being successively portrayed as they exist in the whole series ; or (2) one animal (or plant) may be selected as a type and treated of in detail, other types, successively more _ divergent in structure from the first, being described afterwards. In following the latter mode, we may either begin with one of the most simply organised of living creatures and gradually ascend to the highest and most complex in structure; or we may commence with the latter, and thence descend to the consideration of the lowest kinds of animated beings. Historically, it is the latter course which has been viii PREFACE. followed. The bodily structure most interesting to man, his o^vn, was the first studied (directly or indii-ectly), and the names now given to dift'erent parts of the bodies of the lower animals have been mainly derived from human anatomy. The descending course is also that which seems, on the whole, preferable, for thus, by commencing with the class of animals to which man belongs, we may proceed from the more or less known to the unknown, and from that which is comparatively familiar, to that which is strange and novel. Having then chosen to begin the study of Animals and Plants with that class to which we belong, it might perhaps be expected that Man himseK would be chosen as the type. But a fresh description of human anatomy is not required, and would be comparatively useless to those for whom this work is especially intended. For a satis- factory study of animals (or of plants) can only be carried on by their direct examination — the knowledge to bo obtained from reading being supplemented by dissection. This, however, as regards man, can only be practised in medical schools. Moreover, the human body is so large that its dissection is very laborious, and it is a task generally at first unpleasing to those who have no special reason for undertaking it. But this work is intended for persons who arc interested in zoology, and especially in the zoology of beasts, birds, reptiles, and fishes, and not merely for those concerned in studies proper to the medical profession. The problem then has been to select as a type for examination and comparison, an animal easily obtained and of convenient size ; one belonging to man's class and one not so different from him in structure but that comparisons between it and him (as to limbs and other larger portions of its frame) may readily suggest themselves to the student. Such an animal is the common Cat. In it wo, have a convenient and readily accessible object for refer- ence, while the advantages which would result from the selection of Man as a type will almost all be obtained without the disadvantages of that selection. The study of the zoology of the Cat, as here treated, will also give the earnest student of Biology the knowledge of anatomy, physiology, and kindred sciences, which is necessary to enable him to study profitably the whole class of animals to which it belongs and to which we belong — the class of Mammals. The natui-al history of that entire class will be treated of in a companion volume, to which the present work may serve as an introduction — all the needful anatomical terms and relations (as they exist in the selected type) being here once for all explained. The present volume is expressly intended to be an introduction to the natural history of the whole group of hack-honed animals (since they are all formed according to one fundamental plan) ; but the subject has been so treated as to fit it also to serve as an introduction to Zoology generally, and even to Biology itself: the main relations borne by cats, not only to the leading groups of animals, but also to plants, being here pointed out. The sciences subordinate to Biology are also enumerated and defined. It has been thought better not to separate the study of physiology fi*om that of anatomy, and, accordinglj^, an explanation of the functions performed by each different system of parts of which the body is made up, will be found to follow the account of their structure. I am indebted to my friend Professor Flower for the use of his valuable illustrations of the skulls of the Carnivora, as also to the Zoological Society, from whose Proceedings they are, with some other illustrations, extracted. I desire also to express my thanks to Professor Allen X FREFACE. Thomson, M.D., E.E.S., and to Messrs. Longmans & Co., Messrs. Cassell & Co., and Messrs. Kegan Panl & Co., for the use of various electros. Dr. Murie, F.L.S., has had charge of many of the wood- cuts, certain of which — representing ligaments, viscera, and salivary glands — have been drawn from his dissections and under his supervision. I have to thank Mr. Alban Doran, who has made careful dissections of the internal ear and portions of the generative organs, and also Mr. P. Percival Whitcomb and my son Mr. Frederick St. G. Mivart, for more or less assistance. To Professor Cope I am much indebted for very kindly sending me proofs of unpublished plates of American fossils described and named by him. I have also to express my obligation to Mr. Wm. Pearson (of the College of Surgeons) for making some excellent dissections, from which certain of the illustrations are taken. Original drawings have also been made from specimens preserved in the museum of the Eoyal College of Surgeons and in the British Museum. The di-awings have (with the exception of six figiu'cs of fossil remains) been executed by Mr. C. Berjeau and engraved by Mr. Ferrier. I feel bound to express my sense of the skill evinced in theii* execution. CONTENTS. CHAPTEE I. INTRODUCTORY. SECT. 1. The Cat as a domestic animal 2. Its scientific interest 3. The Wild Cat . 4. Origin of the Domestic Cat 5. The Egyptian Cat 6. The different breeds of the Do mestic Cat . 7. Habits .... 8. In what the scientific study of the Cat consists . PAGE 1 SECT. PAGE 9. The sciences subordinate to Biology — different kinds of anatomy. .... 9 10. Physiology and its subdivisions . 10 11. Taxonomy .... 11 12. Hexicology . . . . . 11 13. Phylogeny . . . .11 14. Order to be followed in tliia Work 11 15. Chemical composition of the Cat's body . . . .12 CHAPTER II. THE CAT S GENERAL FORM. THE SKIN AND ITS APPENDAGES. SECT. PAGE 1. The general constniction and symmetrical relations of the Cat's body . , . . 14 2. The skeleton .... 16 3. Connective tissue . . . 16 4. Cartilage .... 18 5. Bone 19 6. The process of ossification . . 20 7. The growth of bone . . . 20 8. The composition of the skeleton . 21 9. The external skeleton , , 21 SECT. 10. The epidermis 11. The dermis PAGE 21 22 12. The claws .... 22 1.3. The hair. 22 14. Mucous membrane , 24 15. Epithelium and corium 10. Teeth .... 26 27 17. The milk dentition . 29 18. Dental formula . 19. Minute composition of the teeth 20. Their modes of formation , 30 31 32 xu COKTENTii. CHAPTER III. THE SKELETON OF THE HEAD AND TRUNK. SECT. PAGE SEC T. PAGE 1. The endo-skeleton , , 34 21. The ligaments and mobility of 2. Its divisions and subdivisions . 34 the thorax . . 55 3. The backbone . 35 22. The skull considered generally . 56 4. The parts of a vertebra , 35 23. The occipital bone . 61 6. Vertebral categories . 36 24. The parietal . . 62 6. The dorsal vertebras . . . 36 25. The frontal. 63 7. The lumbar vertebroe 39 26. The temporal . 64 8. The cervical vertebrte . . 40 27. The sphenoid 69 9. The axis . 43 28. The ethmoid . 71 10. The atlas . . . 44 29. The maxillo-turbinal . 72 11. The sacrum 44 30. The maxilla . 72 12. The caudal vertebrae . , , 46 31. The pre-maxilla . . . . 73 13. The vertebral series as a whole . 47 32. The malar 74 14. The ventral part of the spinal 33. The nasal .... 74 skeleton . 49 34. The lachrymal . 75 15. The sternum . 49 35. The palatine 75 16. The ribs . , , 50 36. The vomer .... 76 17. The costal cartilages . , 52 37. The mandible . . . . 77 18. The thorax as a whole . 52 38. Thehyoid .... 77 19. The ligaments and mobility of 39. The skull examined externally, the spinal column . . 52 internally, and in sections . 78 20. The union of the axis and atlas . 54 40. The ligaments of the skull 86 41. The cranial skeleton as a whole . 87 CHAPTER IV. THE SKELETON OF THE LIMBS. SECT. 1. The appendicular skeleton and its divisions, and the bones of the pectoral limb . 2. The scapula and clavicle . . 3. The humerus .... 4. Tlie radius ..... 5. The ulna 6. The carpus 7. The mcfcicarpus 8. The phalanges . . . . 9. The ligaments of the pectoral limb 10. A general view of the pectoral apixjndicular skeleton . . 11. The bones of the pelvic limb . 12. The 08 innominatum • AGE SECT. PAGE 13. Tlic femur . • • • 107 14. The patella . • 109 89 15. The tibia . , • ■ • 110 89 16. The fibula • • • 112 90 17. The tarsus . , • • • 113 93 18. The metatai-sus • • . 115 95 19. The phalanges . . 116 96 20. The ligaments of the j)elvic 98 limb . . 116 99 21. A general \iev, r of the pelvic 100 append icuhir skeleton . , 119 22. Comparison of the sectoral and 102 pelvic parts of the > ain>eudicu- 103 lar skeleton. . 119 104 23. The joints , • » • • 120 CONTENTS. , CHAPTER V. THE cat's muscles. SECT. 1. The muscles in general 2. Muscular tissue . 3. Its properties . 4. Different kinds of muscles . PAGE 121 124 126 128 5. 6. Their actions . The classification of muscles . Muscles of the head and neck 129 130 131 SKOT. PAGE 8. Muscles of the trunk and tail . 136 9. Muscles of the fore-limb . .145 10. Muscles of the hind-limb . . 154 11. Comparison of the muscles of the fore and hind limbs . .163 12. Summary of the Cat's myology . 164 CHAPTER VI. THE CATS ALIMENTARY SYSTEM. 8KCT. PAGE SECT. PAGH 1. In what alimentation consists . 165 11. The pharynx , , , . 174 2. Food and waste . . . . 165 12. The oesophagus . . .175 3. Intussusception and dialysis 166 13. The abdominal cavity and its 4. Crystalloids and colloids . 167 contents 176 5. Digestion 167 14. The stomach . , . ,177 6. Summary of the alimentary 15. The small intestine . . . 180 processes and organs 168 16. The caecum and large intestine . 182 7. Mucus , . ... 169 17. The pancreas . . . .183 8. The mouth . . . . 170 3 8. The liver 184 9. The tongue 171 19. The peritoneum . . .189 10. The salivary glands and secretion 172 SECT. 1. The essential nature of the cir- culating system and its com poncut i^arts 2. The blood .... 3. Lymph .... 4. The sti-ucture of the arteries 5. The structure of the veins 6. The capillaries . 7. The lymphatics 8. The heart .... 9. The great blood-vessels 10. The divisions of the heart . 11. The circulation 12. The valves of the heart CHAPTER VII. THE cat's ORGANS OF CIRCULATION. PAGE 192 193 195 196 196 197 198 199 201 201 203 204 SECT. PAGE 13. The auricles and ventricles 205 14. The course of the arteries 206 15. The aorta .... 206 16. The carotid arteries 208 17. The subclavian artery 209 18. Tlie axillary artery . . . 209 19. The thoracic and the abdominal aorta ..... 210 20. The iliac artery , . . . 212 21. The external iliac arteries 213 22. The course of the veins . . 214 23. The portal system . 216 24. The azygos vein . . . . 217 25. The lymphatics 217 XIV CONTENTS. CHAPTER VIII. THE cat's organs OF RESPIRATION AND SECRETION. SECT. 1. In what respiration consists 2. The elimination of water and the generation of heat 3. The trachea .... 4. The lungs 5. The mechanism of respiration . 6. The larynx . . • • 7. The voice .... 8. Secretion, in what it consists . 9. Waste products 10. The kidneys . . . • 11. The ureters .... 12. The bladder .... PAGE SECT. PAGE 220 13. The supra-renal capsules . . 237 14. The thyroid body . 237 222 15. The thymus . 237 223 16. Other ductless glands . . 237 224 17. The sijlcen . 238 225 IS. The mammary glands . . 239 226 19. Reproduction . . 240 229 20. The male generative organs . . 241 230 21. The testis . 243 232 22. Its product . 245 232 23. The female generative organs . 245 235 24. The ovary .... . 248 235 25. Its product . . . 250 CHAPTER IX. THE cat's NERVOUS SYSTEM AND ORGANS OF SENSE. SECT, 1, 2. 3. 4. C. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. PAGE SECT Preliminary view of the functions 21. of the nervous system . 252 22. Sensation . . ... 253 23. The main divisions of the nervous 24. system .... 253 25. Nervous tissue . . . . 253 26. Membranes of the cerebro-spinal 27. axis 256 The spinal cord or niyelon . 257 28. The brain 259 The nerves .... 269 29. The olfactory nerves . . . 270 30. The optic nerve 270 31. The third and fourth nerves 271 The fifth nci-v-e . . . . 271 32. The sixth and seventh nerves . 273 33. The eighth nerve 274 The ninth, tenth, eleventh, and 34. twelfth nerves . . . 274 Suramai7 of the cranial nerves 275 35. The spinal nerves . 276 The brachial plexas and nerves ob. of the fore-limb . . . 278 37. The plexus and nerves of the hind-limb . . . . 281 38. The nerves of the tail 283 The sympathetic system . . The organ of touch . The organ of taste The organ of smell . The organ of sight . . . The organ of hearing Analogies between the ear and the eye ..... The function of the nervous system generally . Conditions of its exercise . . Thefunctions of thespinal nerves. The functions of the cranial nei-ves .... The functions of the si>inal cord The functions of the medulla oblongata . . . . The functions of the pons varolii, corpora quadrigemina and cerelicllum . . . . The functions of the cerebrum . The functions of the sympathetic system . . . . . Sleep Kxternal and internal sensations PAOB 283 285 285 286 288 295 303 304 307 307 309 309 310 311 312 312 313 313 CONTENTS. XV CHAPTER X. THE DEYELOPMEXT OF THE CAT. SECT, 1 What is meant by its develop- ment ..... 2 Change in the ovum antecedent to impregnation 3. Actions of the spermatozoa 4. Yelk segmentation 5. First appearance of the embryo and the earlier stages of its growth 6. Nutritive conditions and mater- nal modifications . 7. Development of the tissues . 8. Of the axial skeleton PAGE 317 317 318 318 320 326 329 332 SECT. 9. Of the skull .... PAGE 335 10. Its ossification 338 11. 12. Development of the limbs . . Of the muscles 339 341 13. 14. Of the alimentary canal and its appendages . . . . Of the blood and vascular system 341 345 15. 16. 17. Of the lungs and adjacent parts . Of the urinary and generative systems ..... Of the nervous system and organs of sense .... 349 350 355 18. Summary and result . . . 364 CHAPTER XI. THE PSYCHOLOGY OF THE CAT. SECT. PAGE 1. What the study of Psychology is 365 2. The Cat's psychical powers 366 3. Language — its different kinds . 371 4. Mental powers which arc not Ijossessed by the Cat 3/2 5. All its powers are coordinated . 374 6. Its hierarchy of functions 374 7. Its principle of individuation . 375 8. This cannot be merely nervous activity .... 376 9. Certain anatomical and patho- logical facts . . . . 377 10. The Cat has consentience . 378 SECT. 11. The relations of psychical and physical phenomena 12. The meaning of the term ' Psyche,' or ' Soul,' and the question of the existence of such an entity 13. Objections considered . . . 14. The Cat not a mere automaton . 15. What the Cat in itself is . 16. Immaterial realities . . . 17. Definitions . . . . 18. The bearing of Psychology on de- velopment PAGE 578 380 381 382 384 385 386 386 CHAPTER XII. DIFFERENT KINDS OF CATS. SECT. 1. What are 'kinds,' 'species,' and ' varieties ? ' 2. Morphological and physiological species . . . . 3. Zoological nopifiiiclature . . PAGE I SECT. PAGE t 4. The Lion, Tiger, Leopard and 390 1 Ounce ... . .392 i 5. The Pnma and Jaguar . . . 397 391 I G. The Clouded Tiger and Thibet 392 1 Tiger-cat ; the Spotted Cat, XVI CONTENTS. CHAPTER XU— continued. SECT. PAGE the Bay Cat, the Fishing Cat, the Leopard-cat, the Wagati and the Marbled Tiger-cat . 398 7. The Serval, the Golden-haired Cat, the Grey African Cat, and the Servaline Cat . . . 406 8. The Ocelot, the Margay, Geof- froy's Cat, the Ocelot-like Cat, the Yaguarondi, the Eyra and the Colocollo . . . 408 9. The Rusty-spotted Cat, the Chi- nese Cat, the iSmall Cat, Jer- dou's Cat, the Java Cat, the hushy-tailed-red-spotted Cat, the Small -eared Cat, the Large-eared Cat, the Flat- headed Cat and the Boraean Bay Cat 413 10. The Egjrptian Cat, the Common Wild Cat, the Indian Wild SECT. Cat, the Common Jungle Cat, the Ornate Jungle Cat, the Steppe Cat, Shaw's Cat, the Manul and the Pampas Cat . The Northern Lynx, the Pardine Lynx, the Thibet Lynx and the Caracal .... The Common Cheetah and the Woolly Cheetah . . . Review of living Cats Extinct Cats . . . . Machjei'odus .... 16. Hoplophoneus and Pseudoslurus 1 7. Nimravus and Dinictis . . Archselurus .... Pogonodon and Eusmilus Fossils of uncertain nature, and summary of fossil cat 11 12 13 14 15 18. 19. 20. PAGE 419 424 427 430 431 432 433 435 43i 437 43 Ol CHAPTER XIII. THE cat's PLACE IN NATURE. SECT. PACE 1. What is needed to be known in order to answer the question " What is a Cat ? " . . . 440 2. The Cat's most general mor- phological and physiological characters . . . .440 3. Tliese distinguish it from all non-living beings . . . 441 4. An objection considered . . 442 5. The cliaracter of the Cat as a living being . . . 445 C. What is implied in saying "the Cat is an animal " . . 445 7. The principles of zoological classification . . . . 449 8. The various sub-kingdoms of animals .... 450 9. The character of the Cat as a backboned animal . . . 454 10. The iirovinccs and classes of backboned animals — espe- cially the class of fishes . 455 11. The characters by which tlie Cat differs from all fishes . . 458 12. The class Batrachia of the pro- vince Branchiata . . . 459 13. The characters by which the Cat differs from all Batrachians and from all Branchiata . . 460 SECT. PACE 14. The class Reptilia of the pro- vince Monocondyla . .461 15. The characters by which the Cat differs from all Reptilia . . 462 16. The class A ves or Birds . . 462 17. The characters by which the Cat differs from all birds, from all Monocondyla, and from all non-mammalian Vertebratii . 465 18. The sub-classes and orders of the class Mammalia . , 466 19. The characters by which the Cat differs from the sub-classes of Mammalia to which it does not belong .... 469 20. The characters by which the Cat's order differs from the other orders of placental mammals 471 21. The sub-orders and families of Carnivora . . . . 474 22. The characters of the Cat's sub- order itiluroidea . . .475 23. The families of the Cat's sub- order ..... 481 24. The peculiarities of the Cat's own family— Fclidaj . . . 486. 25. Position of the genus, Fells, and the Cat's place amongst all other creatures . . . 489 CONTENTS. xvu CHAPTEK XIV. THE CAT S HEXICOLOGY. SECT 1 living The various relations of creatures to their environment 2. The Felidse and physical condi- tions, such as warmth, light, and moisture . . . . 3. The geograjjhy of the Felidce 4. Zoological geographical regions . 5. The relations of the Felidse to time . . . . • PAGE 494 494 495 497 501 SECT. 6. Certain -.1 9. 10. elementary facts of geology The paUeontology of the Felidse . Non-feliue mammalian remains contemporary with or antece- dent to fossil cats The inter-relations between cats and other living creatures The parasites of cats PAGB 501 502 503 508 509 I CHAPTEE XV. THE PEDIGREE AND ORIGIN OF THE CAT. g-"CT. PAGE 1. Meaning of the Cat's 'pedigree ' and ' origin' . . . 512 2. No present need to argue in favour of evolution . . 512 3. Probability of the Cat's descent through viverrine ancestors . 512 4. The probable genetic relations or phylogeny of the .ffiluroidea 513 5. The probable phylogeny of the Carnivora . . . .514 6. Primitive mammals probably not marsupial . . . . 515 7. Summary of the Cat's pedigree . 517 8. Premammalian ancestors un- known .... 518 9. Different possible modes of evolu- tion 519 10. What are 'species,' 'genera,' ' families, ' ' orders, ' and ' classes ' ? . . .520 SECT. PAGE 11. We have experience of the origin of all of these . . . . 521 12. What our experience should lead us to expect as to the origin of Cat species . . 522 13. We seem to have experience as to the origin of life itself . . 524 14. Our experience as to modes of origin .... 524 15. Necessity of the idea of an in- ternal force . . . . 525 16. Psychogenesis .... 526 17. The cause of Psychogenesis . . 526 18. Prototypal ideas . . .528 19. Science is a knowledge of causes, and a knowledge of all causes is necessary for perfect science 530 20. Utility of the study of ' types ' . 530 LIST OF ILLUSTRATIONS. External form of Wild Cat and figure of the skeleton, showing the relations of the latter to the external form Frontinpiece FIG. PAGE 1. Muzzle of the cat, seen in front i . .14 2. A diagrammatic vertical section of the cat's body taken antero-poste- riorly through the median plane 16 3. Connective, adipose, and elastic tissue 17 4. Hyaline cartilage and fibro-caitilage — greatly magnified . , . . 18 5. Vertical and horizontal sections of a fragment of thigh-bone — greatly magnified .19 6. Vertical section through the thigh-bone of a young cat, showing epi- physes 20 7. Touch-corpuscle and Pacinian body 23 8. Section of a cat's vibrissa 24 9. Sole of the cat's fore-paw, showing the pads 25 10. Similar view of the hind-paw ih. 11. Ciliated epithelium cells. From Quain's Anatomy ib. 12. The cat's dentition 27 13. Milk dentition of the cat 30 14. Microscopic tooth structure 31 15. A fragment of enamel — greatly magnified. From Quain's Anatomy — after KoUiker 32 16. Three views of fifth dorsal vertebra 37 17. Tenth and eleventh dorsal vertebrae 39 18. Three views of fifth lumbar vertebra 40 19. Three views of fifth cervical vertebra 41 20. Five views of axis vertebra 42 21. Five views of atlas vertebra 43 22. Three views of sacrum 45 23. Ventral aspect of vertebral column 48 24. Skeleton of thorax, seen ventrally 49 25. First, sixth, and thirteenth ribs 51 26. Two views of intervertebral discs 53 27. Ligaments of axis and atlas . 55 28. Dorsal view of skull 56 29. Base of skull 58 30. Front view of skuU 59 31. Occipital bone— two views 61 32. Interparietal bone — two views 62 33. Parietal bone — two views 63 34. Frontal bone — two views **• 35. Temporal bone — two views 65 XX LIST OF ILLUSTRATIONS. FIG. PAGK 36. Section of the temporal bone of a tiger. From Professor Flower's paper published in the Pro. Zool. Soc. 1869, p. 17 67 37. Sphenoid bone — two views 68 38. The right maxilla, seen internally and externally 72 39. The premaxilla — two views . . ....... 74 40. The malar bone — two views • . . . . ib. 41. The nasal bone — thre3 views ... * 7.5 42. The lachrymal bone — two views ib. 43. The palatine bone — three views ib. 44. The mandible — inside view 76 45. Ventral and side view of the os hyoides, larynx, and trachea ... 78 46. Side view of skull 80 47. Back view of skull 81 48. Outline vertical section of skull to show cranial angles . . . . 84 49. Vertical section of skull, showing median ethmoid ib, 50. Vertical section of anterior half of skull to show nasal cavity and frontal sinus 86 51. Scapula, external aspect 90 52. Scapula, seen internally and from below 91 53. Humerus — four views 92 54. Humerus —inner side ........... 93 55. Eadius — four views 94 56. Ulna — three views 95 57. Skeleton of fore-paw — its palmar aspect 97 58. Skeleton of fure-paw — its dorsal aspect . • ib. 59. Bones of middle digit 98 CO. Vertical section through the bones of the fore-paw of a j'oung cat — to show epiphyses ib. 61. Ligaments of shoulder — two views . . . . . . . . 100 62. Ligaments of elbow — two views .101 63. Ligaments of digit — to show the mechanism of the retractile claw . 103 64. Pelvis — antero-ventral view . . . 104 65. Os innominatum — outer view 105 66. Os innominatum — seen from within . . ...... ib. 67. Femur — two views 108 68. Femur — four views 109 69. Tibia and fibula — seen in front 110 70. Tibia and fibula — seen posteriorly ib. 71. Tibia seen within, proximally, and distally Ill 72. Skeleton of hind-paw — plantar surface 114 73. Skeleton of hind-paw — dorsal surface . ih. 74. Ligaments of knee-joint 117 75. Vertical section through knee-joint 118 76. Muscular tissue 126 77. Muscles of right fore-qudrter 136 78. Muscles of sternum .... 139 79. Muscles of ventral surface of trunk 140 80. Extensor (dorsal) muscles of right fore-limb 146 81. Muscles of flexor (ventral) surface of right fore-limb .... ib. 82. Superficial muscles of outside of right thigh 154 83. Deep muscles and tendons of outside of right hind-limb. . . .155 84. Muscles of inside of right thigh 157 85. Flexor muscles of leg 159 86. Surface of palate 170 LIST OF ILLUSTRATIONS. xxi 87. Dorsum of tongue • • • . -i ' -^ 88. Salivary glands ^''^ 89. Viscera ?« «)Yk ^'^ 90. The stomach and pancreas . 177 91. Magnified vertical section of wall of pig's stomach. From Quain's Anatomy — after Kolliker 1^8 92. Two gastric glands, greatly magnified. From Quain's Anatomy— after Heidenhain '^' 93. Intestinal canal, from oesophagus backwards 179 94. Intestinal villi — three views 180 95. Caecum — two views 1°^ 96. Liver seen from behind 18-1 97. Magnified section of an hepatic vein. From Quain's Anatomy— after Kiernan 1^*^ 98. Magnified section of a portal canal. From Quain's Anatomy— after Kiernan ....... ...... 187 99. Blood-corpuscles 1^5 100. Veins with their valves. From Quain's Anatomy 197 101. Diagram of a lymphatic gland. From Quain's Anatomy . . . 199 102. Sections of the heart 200 103. Diagram of the adult circulation (seen dorsally) 202 104. Great blood-vessels 207 105. Vessels and certain viscera of abdominal cavity 212 106. Cartilages of larynx 227 107. The lar3Tix and glottis as seen laterally and above, and both contracted and expanded 228 108. Diagram of different gland forms. From Quain's Anatomy . . . 231 109. The kidney, entire and in section ........ 232 110. Diagram of a Malpighian body. From Quain's Anatomy — after Kolliker . 234 111. Diagram of minute circulation of kidney. From Quain's Anatomy — after Bowman ^^• 112. The thymus and thyroid glands • . . 236 113. The cat's spleen 238 114. Mammary glands 239 115. Male generative organs 242 116. Diagram of testis. From Quain's Anatomy 244 117. Spermatozoa 245 118. Section of cat's ovary, much magnified. From Quain's Anatomy— after Schron 248 119. Another section, still more magnified. From Quain's Anatomy — after Schron . . 249 120. The ovTim 250 121. Nerve fibres, magnified. From Quain's Anatomy — after Bidder and Volkmann 254 122. Ganglionic nerve-cells, greatly magnified. From Quain's Anatomy — after Valentin 255 123. Brain of the cat in situ — covered on the left side by the pia mater . . 257 124. Sections of spinal cord, somewhat enlarged. From Quain and Sharpey (Allen Thomson) 258 125. Lateral view of cat's brain 259 126. Upper surface of cat's brain 261 127. Upper part of cat's brain — the hemispheres much divaricated to show the corpora quadrigemina. From a specimen in the College of Surgeons Museum 262 xxii LIST OF ILLUSTJRATIONS. FIG. PAGE 128. Base of the cat's brain 204: 129. Vertical, loagitudinal section of the cat's brain 2<)6 130. Cranial nerves 272 131. Brachial plexus and nerves 278 132. Nerves of fore-paw 280 133. Lumbar and sacral plexuses and nerves ih. 134. Vertical section of eye 290 135. Diagram of retina 292 136. The lens. From Quaiu's Anatomy — after Arnold 203 137. Section through the internal ear 297 138. Bony labyrinth and auditory ossicles. From specimens in the College of Surgeons • 300 139. Two rods of Corti highly magnified. From Quain's Anatomy . . . 302 140. Termination of auditory nerves. From Quain's Anatomy — after Max Schultze 303 141. Early stages of yelk segmentation 319 142. Single ovum, more advanced and bisected. From Haeckcl's " Evolution of Man ■■' 320 143. Two ova, showing incipient stages of formation of germ area . . . ib. 144. Section of genn area. From Hseckel's " Evolution of Man " . . . 321 145. Three views from above of the earliest stages of the embryo's develop- ment. From Quain's Anatomy — after Bischoflf ib. 146. More advanced embryo, seen from above, showing proto-vertebrse. From Quain's Anatomy 322 147. Diagram representing four transverse sections of embrjo at different stages of development 323 148. Five diagrammatic views of the dcveloi)ment of the amnion and allantois. From Hajckcl's "Evolution of Man ■' — after Kolliker .... 324 149. Diagram of the placental connexion of the embryo with the uterus . . 326 150. The embryo cat in the uterus in its membranes. From Owen's Anatomy of Vertebrates — after BuflEon and Daubenton .... 328 151. Longitudinal section of an embryo. From Quain's Anatomy . . . 332 152. Diagram of foetus, showing the visceral arches and budding limbs . . 334 153. Lateral view of head of embryo i)ig, showing the visceral arches. From Quain's Anatomy — after Parker 336 154. Ventral aspect of the same ib. 155. Longitudinal, vertical section through embryo, showing incipient ali- mentary canal, &c. From H;eckers " Evolution of Man" — after Baer. 342 156. Diagram of the foetal arteries and veins 347 157. Diagram of the foetal circulation through the heart and aorta . . . ib. 158. Diagram of the development of the generative organs .... 353 159. Portion of ovary of kitten, showing fii-st development of ova — from Foulis 355 IGO. Diagram of the dcvclopmunt of the brain 357 161. Four figures of the brain of an embryo kitten. From Quain's Anatomy, — after Rcichert 358 162. Development of the eye— from Quain's Anatomy 362 163. A lladiolarian (Dorataxjjis j'o^ i/ti )ui.sf ra)—i;rciii\y magnified . . . 378 164. The same, only partially developed — (Both from the Journal of the Linnean Society) 379 165. Skull of the Leopard — from Pro. Zool. Soc 395 166. The Ounce (Felix 7/«c/«)— from Mr. Elliot's Monograph . . . . ib. 167. Skull of the Ounce— from Pro. Zool. Soc 396 ] 68. The Clouded Tiger (/'. viacrocdix) 398 LIST OF ILLUSTRATIONS. XXlll FIO. Kii). 170. 171. 172. 173. 171. 175. 17(;. 177. 178. 179. 180. 181. 182. 183. 184. 185. 186. 187. 188. 189. 190. 191. 192. 193. 19i. 195. 196. 197. 198. 199. 200. 201. 202. 203. 204. 205. 206. 207, 208. 209. ykuU of the Clouded Tiger — from Pro. Zool. Soc. The Fishing Cat (F. vivcrrina) —aitcv Elliot Skull of Fishing Cat — from Pi'o. Zool. Soc. Skull of the Leopard-Cat — from Pro. Zool. Soc. . Tlic Marbled Tiger-Cat (F. marmorata} . Skull of Geoffrey's Cat — from Pro. Zool. Soc. The Eyra {F. Eijra) The Rusty-spotted Cat (^F. ruhiginosa) — after Elliot The Flat-headed Cat {F. 2da nicrj'-^)— alter Elliot Skull of Flat-headed Cat — from Pro. Zool. Soc. The Manul (F. Maniil) — from a s[)ecimen in the British Museum . The Northern Lyux, variety 7'I«t«t'«/ft^a — fi'om a sj^ecimen in the British Museum The Cheetah {CijncclHrnsjubata) The young Cheetah Skull of Cheetah (De Blainville) Skull of Machccrodus smilodoii (De Blainville) Skull and teeth of Iloplophoneus orcodontis (Cope) . . . . . SkxiW ot Kimrav Its brachijo2)s {Qo\)Q.) Skull of Dmictis eyelojys (Cope) Skull of Archa'lurtis del'dis (Cope) ........ S\i\A\ oiPug(iiiodo)i 2)Jafyc(HJis {Co]}q) ........ Lower jaw and teeth of Fiismilus bldentatus Skull of the Panda (Ailuru-sfidt/cn-f) — from the Pro. Zool. Soc. Skull of the bear ( Ursns a rctos) — from the Pro. Zool. Soc Basis cranii of the bear. From Professor Flower's paper on the Carni- PAGB 399 402 ib. 403 405 411 412 415 418 ib. 423 425 428 ib. vora, Pro. Zool. Soc. Vertical section of the tympanic cavity of the bear — from Professor Flower's paper Skull of an Indian fox ( Vid])es boignhnsis) — from the Pro. Zool. Soc. . Basis cranii of wolf — from Professor Flower's jiaper Section of auditory bulla of dog — from Professor Flower's paper . Skull and dentition of Paradoxurits Crossii — from Pro. Zool. Soc. . . Basis cranii of civet — from Professor Flower's paper .... Basis cranii of Paradoxure — from the same pajjer Basis cranii of ichneumon — from the same paper ..... Basis cranii of hyjena — from the same paper . . . . . . External form of Cryptoprccta Skull of Cryptoprocta — after Milne-Edwards Basis cranii of Crjqitojirocta — from Professor Flower's paper The pads of the feet of Cryptoprocta — after Milne-Edwards . . . Basis cranii of tiger — from Professor Flower's paper .... Section of tiger's auditory bulla (Fig. 36 repeated) Diagram of cat's possible pedigree 429 433 434 ib. 435 436 437 438 474 475 476 477 478 ib. 479 480 481 ib. 482 484 483 ib. 486 ib. 487 488 518 EBRATA. Page 383, line 20 from bottom, for "Mr. Lawes," read "Mr. Lewes." 429 ,, 8 ,, ,, /or "Felis lanea," rmci "Cyncelurus Ian ea.'' 450 ,, 14 ,, ,, /o?* " Enteropnemata," reaci " Eateropneusta. y THE CAT. CHAPTER I. INTRODUCTORY. § 1. Whether it is the Cat or tho Dog which is the most domestic of all our domestic animals, is a question which may be disputed. The greater intelligence and affection of the dog, cause men generally to prefer it to its rival. As the eager partner of our sports, or the faithful guardian of house or homestead, it is of especial value. Yet the cat is so largely self-supporting and so useful an ally against unwelcome intruders, that it is the inmate of a multitude of humble homes wherein the dog has no place. The cat also is favoured by that half of the human race which is the more concerned with domestic cares ; for it is a home-loving animal and one exceptionally clean and orderly in its habits, and thus naturally commends itself to the good will of the thrifty housewife. Moreover, though it is generally much less demonstrative in its affection than is the dog, yet cats differ as men do, and some in- dividuals manifest strong feelings of regard for one or other members of the family wherein they make their homes. Cats are even sometimes made use of to obtain food for their owners, the latter availing themselves of the habit which cats have of bringing home prey.* The Domestic Cat is an animal so common and familiar that its utility is sometimes apt to be lost sight of. To realise its usefulness we must imagine ourselves in a land where no such an animal is known, but where the annoying creatures upon which it preys shall have multiplied with that rapidity natural to them. The familiar talc of AVhittington may serve to illustrate what would be the effect of its introduction into such a land. It has been calculated that a single cat may devour twenty mice in one day ; but this of course is by * Tims, several rabbits will sometimes be brought liome hy a cat in a single day. 2 THE CAT. [CHAP. i. no means tlie limit of its powers of destruction. Its effect in putting to flight tlic creatures it pursues, is again far in excess of its destructive energy. Were every cat in England simultaneously destroyed, the loss througli the entailed increase of vermin would be enormous. § 2. But however much this animal ma}'' deserve our esteem, or win our admiration, by its shapely form and graceful movements, it certainly has very special claims on the attention of lovers of biological science. For in the first place its organization, considered absolutely in itself, is one of singular perfection, and the adaptation of means to ends which it displays is truly admirable. If, however, we compare its organization with that of other animals, wo shall by so doing not only gain a better appreciation of its structural per- fections, but also become acquainted with a variety of relations conveying useful lessons in anatomy, psychology,* and zoology, and others referring to the past, the present, and even the future history of this planet. § 3. The " Common" (domestic) Cat of our country, and indeed of the continent also, is not the " Common Cat " of zoology. The latter is of course the originally native cat — or wild cat. The domestic and the wild cat may, however, for our present purpose, be considered together, and, thus considci'cd, the events of the last two thousand years have strangely altered the distribution of the cats of this country. That men dwell in cities, instead of in woods, is one effect of civilization. A similar but greater change has been produced with English cats by the same cause. For when Julius Caesar landed here our forests were plentifully supplied with cats, while probably not a single mouser existed in any British town or ^'illagc. The word "cat" appears to be of Roman origin, being probably derivedfrom the Latin word cafus, which word also seems to liave been at the same time the root of the Greek Karra, the old German name rJiazza, and of the softened French form of the word, cJud. The original derivation of the name does not, however, appear to have been as yet ascertained. It occurs in Anglo-Saxon writings with the spelling Catt. It might be supposed that our present domestic cat is simply our own ancient wild cat tamed ; but had it been so and therefore been easily procurable, it would not have been so highly valued as it was even so late as a thousand years after the Roman invasion. But though the domestic cat was thus rare, and therefore ]irccious, tlic wild cat continued to bo common in England during the Middh^ Ages. This is proved by the fact that its fur was then connnonly used for trimming dresses. A canon, enacted in the year 1127, forbad any abbess or nun to use more costly fur than that of lambs or cats, and tlio cat "was an object of chase in ro}'al forests, as is shown by a license to hunt it of * The word Psj'cholofjy is hci"'' "sed in i its proper sense as embracing Physiologj' ts wide and (as the iiullinr believes) in | within its scope. CHAP. I.] INTBODUCTOEY. the date 1239, and by a similar charter given by Eicliard the Second to the Abbot of retorborough. » The Wikl Cat is now (thanks to the destruction of our forests, the introduction of fire-arms, and the over-zeal of game-keepers,) extinct in England, and perhaps in Wales also, though it lived here till within fifty, and in Wales till M'ithin twenty years ago. In Ireland it seems never to have existed, and the stories we read of Irish wild cats probably refer to the progeny of domestic cats run wild. This is the opinion of Dr. Hamilton, F.Z.S., who has paid great attention to this subject, and carefully collected and investigated the evidence as to the existence of the wild cat in Ireland. In Scotland it is still far from uncommon, and is especially frequent in Inverness, Eoss-shire, Sutherland, and on the west coast of the Highlands, where the recent increase of rabbits (animals so useful to it as good food,) seems to have occasioned some increase in the number of wild cats. These animals exist also in Skyc, but not in the Western Isles. On the continent the wild cat is found in Southern Paissia, and the adjacent parts of Asia, Turkey, Greece, Hungary, Germany, Dalmatia, Spain, Switzerland, and, though now very rare, France.* It does not appear to exist in Norway or Sweden. § 4. Our Domestic Cat seems to have come to us (like our other domestic animals) from the East, and is probably a descendant of the old domestic cat of Egypt, which, as the granary of the ancient world, might well have been the country in which the animal was originally tamed. In the Egyptian Gallery of the British Museum is an excellent painting of a tabby cat, which seems to be aiding a man who is capturing birds. It is mentioned in inscriptions as early as 168-1 B.C., and it was certainly domesticated in Egypt thirteen hundred years before Christ. The earliest known representation of the cat as a domestic animal and pet, is at Leyden in a tablet of the 18th or lOth dynasty, wherein it appears seated under a chair. In Egypt, it was an object of religious Avorship and the venerated inmate of certain temples. The goddess Pasht or Bubastis, the Goddess of Cats, was, under the Roman Empire, represented with a cat's head. A temple at Beni-Hassan, dedicated to her, is as old as Thothmes IV. of the 18th dpiasty, 1500 B.c.f Behind that temple * One wild cat at the least has been killed in France between 1815 and 1830. t Dr. Birch has kindly informed me that the earliest representation of the cat, with which he is acqnainted, the date of which is certain, is on tomb No. 170 of the Berlin ilnseura, apparently of about 1600 B.C. ; but that it also figures on a tablet which from its style appears to be two hundred years older — as ]iart of the name of a woman, "Main" or cat. It also appears in hunting scenes of the 18th dynasty, and in rituals written under that dynasty, but pro- bably repetitions of a much earlier text. It is mentioned in tlie 17th chapter of the Eitual, and the coffins of the lltli dynasty are inscribed with that chapter, Avhicli, according to Lepsius, would carry us back to about 2-100 B.C. In a copy of the Eitual of B.C. 1500, its 33rd chapter has the text, "thou ha.st eaten the rats liatefiil to l!a (the Sun), and thou feedest on the bones of the impure cat." In Egypt an animal, thougli sacred in one city, might be regarded ns impure in another cit}'. 4 THE CAT. [chap. I. are pits containing a multitude of cat mummies. The cat was an emblem of the sun to the Egyptians. Its eyes were supposed to vary in appearance with the course of that luminary,* and likewise to undergo a change each lunar month, on which account the animal was also sacred to the moon. Herodotus (ii. 66) re- counts instances of the strangely exaggerated regard felt for it by the dwellers on the Nile. He tells us that when a cat dies a natural death in a house, the Egyptians shave off their eyebrows, and that when a fire occurs they are more anxious to save their cats than to extinguish the conflagration. From Egypt it must have been introduced into Greece, and the intimate knov/ledge of Egyptian customs which became common in Eome from the time of Julius and Augustus must have brought into it amongst many other animals a knowledge of the domestic cat. A fresco painting of such a cat was discovered in Pompeii.f It was not a domestic animal amongst the Hebrews, though it was known in India two thousand years ago. It has been suggested by Professor Rolleston,:J: that the domestic animal of the Greeks (used by them for the purposes for which we now use the cat) was the white-breasted marten. But however this may be, there can be no question as to the cat having been domesticated in Europe before the Christian era. There are signs that it was domesticated amongst the people of the Bronze period, and the supposition that it was first introduced into "Western Europe by the Crusaders, is of course an altogether erroneous one. They may however have introduced a distinct race, for if it be true that our domestic cats have mainly descended from the Egyptian cat, it does not follow but that blood from other sources may have mingled with that of the Egyptian breed. Pope Gregory the Great, who lived towards the end of the sixth century, is said to have had a pet cat, and cats were often inmates of nunneries in the Middle Ages. The great value set upon the cat at this period is shown by the laAvs which in Wales, Switzerland, and Saxony, and other European countries, imposed a heavy fine on cat-killers. As compensation, a payment was required of as mucli wheat as was needed to form a pile sufficient to cover over the body of the animal to the tip of its tail, the tail being hold up vertically, with the cat's muzzle resting on the ground. The Wild Cat (Ftiis cdfus) differs from our ordinary domestic cat in that it is more strongly built and larger, with a stouter head and shorter and thicker tail, which is not tapering but of about the same thickness throughout. Its whiskers also are more abundant, and the soles of its feet are, in the males, deep black. Its body is of a yellowish-grey colour, Avitli a dark longitudinal mark along the * Mr. J. .Tenner Woir has found that the eyes of cats will n'!ill3-rlianf,'e colour. f yec Plate 81 of liaccolta do i>iu Wlli Dipinti, i'roni the collections in the lioyal Museum (Napoli, 1854). The oat i.s rciiicsi'utcd as seizing a thrush, and is \ery well drawn. i Sec ( 'aniliridfic Journal of Anatomy and riiysiologv, 1SG8, vol. ii. pp. -17 and 437. CHAP. I.] INTRODUCTORY. back, and with numerous darlcisli stripes dcsccndinp,- more or less vertically down the sides, and marking transversely the limbs. Its tail is ringed witli black, and is black at the end. It is tlius marked like tlic domestic variety called "tabby." One killed near Cawdor Castle measured 3 feet 9 inches from its nose to the end of its tail.* Its savage disposition is very early shown, even the young kittens spitting vigorously at anyone who approaches them. The female makes her nest in hollow trees and the clefts of rocks, and sometimes uses the deserted nest of some large bird. i^ 6. The Egyptian Cat {FcHh nmnkulata) is a native of northern Africa, and was the parent of the cat tamed by the Egyptians, and — if what has been here urged is correct — also of our own domestic cat, possibly with an admixture of other blood. The Egyptian cat is said to be about one-third smaller than the European Avild cat. It is of a yellowish colour, somewhat darker on tbe back and whitish on the belly. There are some obscure stripes on the bod}', which become more distinct on the limbs. The tail is more or less ringed towards its termination, which is black, § 6. Although the differences between the various breeds of the Domestic Cat are small indeed compared with those betAveen dif- ferent races of dogs, still very distinct varieties exist, but their distinctions repose mainly on the colour and the length or quality of the fur, and not on differences of form, such as those we find existing between the Greyhound and the Pug, the Spaniel and the Mastiff. The colours of cats may be divided into black, white, tabby, sandy, tortoiseshell, dun, grey, and what is termed " blue." There arc also cats in which these various colours are more or less mixed. The grey cat is very rare. It is, in fact, a tabby, without the black stripes, except two large stripes over the fore-legs — marks present in most spotted or striped cat-like animals of whatever species. Black cats are remarkable for the clear yellow colour of their eyes. Their coat is rarely entirely black, for there are generally a few white hairs on the throat at the least. When young they show more or less perceptible striped markings. White cats may have blue eyes, or eyes of the ordinary colour — • that is, an obscure yellow with a tinge of green. Those with blue eyes are generally deaf, but they are not always so. It often happens that the eyes of a white cat are not alike in colour ; thus one may be blue and the other yellow. The late Mr. John Stuart Mill told my friend Mr. John Jenner Weir, F.L.S.,t that he had at Avignon a breed of cats the eyes of which distinctly changed colour when the animals were excited. * Mr. Harrison "Weir tells me that tlic largest domestic cat he has seen weighed wenty-three pounds, t This gentleman has acted as judge at numerous cat shows, and I am in- debted to him for very kindly furnishing me with his notes respecting varieties of the domestic cat. THE CAT. [chap. I. The tabby cat may be tlie result of the occasional crossing of the domestic cat by the wild cat. That they do breed together occasion- ally is certain,* and indeed races of domestic cats of different parts of the world will breed with wild cats of the same region. The tortoiseshell cat should be fawn-coloured, mottled with black. Cats thus marked are almost invariably females, while sandy-coloured cats are almost always males. It appears that the sandy tom cat is the male of the breed of which the tortoiseshell is the female — the litters being almost invariably so divided. This fact is very interest- ing, because the sexes of cat-like animals are similarly coloured.! Sometimes, however, sandy cats are female, and there is at least one good instance of a true tortoiseshell tom cat. Such cats, indeed, liavo not unfrcquently been offered, by letter, to the Secretary of the Zoological Society, at very extravagant prices. Probably many of them were male cats of three colours — such as white and tortoiseshell and arey-whitc and sandy — but not the true tortoiseshell. The Royal Siamese cat is of one uniform fawn colour, which may be of a very dark tinge. There is a tendency to a darker colour about the muzzle — as in pug dogs. It has also remarkable blue eyes, and sometimes, at the least, two bald spots on the forehead. It has a small head. The blue or Carthusian cat is a breed v/ith long, soft hairof a uniform, dark greyish-blue tint, with black lips, and black soles to the paws. The Angora, or Persian cat, is remarkable for its great size, and for the length and delicacy of its hair, especially of the belly and throat. INIost commonly its coat is of a uniform white, yellowish or greyish colour, while the soles of its paws and its lips arc often flesh-coloured. Its temperament is said to be sometimes exception- ally lethargic ; but this is certainly not always the case, and may be due to excessive petting for generations. This breed is believed by some naturalists to be descended from an Asiatic wild cat,+ with a shorter tail than that of the Egyptian cat. It is commonly re- ])eatcd in works on Natural History that there is in China a breed of cats with pendent ears ; but the Pere David ^ regards the assertion as an absurd fable. lie has repeatedly sought to find such animals, but has never been able to sec any, or to learn that they existed. * Tlii.s has been asccrtiiincd liy ISlv. A. 1\. Wills, who siicccedud in f^cltin^ the wilil and (hiiucstic cat to hici'd together ill coiilinriiicnt. (Sec ]jaiid and "Water, He])t. 4th, 1875 ; anil tlic Zoolorjist for 1873, p. 3574 ; and lor 1S7(J, pj). 48(J7 and 5038.) Mr. S. ('. B. I'usey lias also surcessrully crossed the wild and domestic cat, and scvi'ral kittens resnltinj; iVoni this cross have been sent to the gardens of the Zoological Society of London. 'J'his interbrccdiug is remarkable, seeing that the jieriod of gestation of the wild cat is sixty-eight days, or twelve days longer lliaii that of the domestic animal. f Tlic only exception 1 liiive met with is the Yaguaroiidi of Aineiica, in which species tla^ feiiiali! is said to be of a lighter and brighter colour than the male. J Pallas says that cats like the Angora cat are brought to Sil)eria from (.'hina. Zoographia Kusso-Asiatica, vol. i. ji. 28, note 3. S The well-known Laiiarist missionary and naturalist, who has made so many iuterestbig discoveries in China and Thibet. CHAP. I.] INTRODUCTORY. 7 la Pegu, Siara, tiud Barniali, there is a race of cats* — the Mala// Cat — with tails only of half the ordinary length, and often contorted in a sort of knot, so that it cannot be straightened. t The true short- tailed or tailless cat — the Manx Cat — has also the hind-legs relatively long. Mr. J. J. AVeir tells mo he has seen one which had the fore- legs so short as to be useless in walking, and the animal sat up like a kangaroo. + Tailless cats are not, however, the only cats to be found in the Isle of Man ; some cats there have tails ten inches long,§ a fact probably due to the introduction of long-tailed cats from England, Scotland, or Ireland. In cross-breeding the progeny seem generally to resemble the father as to length of the tail.|| A tailless breed of cats also exists in the Crimea. The Momhci^ Cat of the coast of Africa is said to be *[[ covered with short stiff hair instead of the ordinary sort of hair. The Paraguay Cat ** is but a fourth of the average size of our domestic cats, has a long body with short, shiny, scanty hair, which lies close, especially on the tail. In South America there is said to be also a race of cats which have ceased to give forth cries like those by which our own cats are wont to give expression to their emotional sensibility. It is to be wished that this last breed should be introduced into this country. Yet the breed would probably not persist, for the reason which seems to limit the formation of new races ; for the wandering nocturnal habits of the species defeat most attempts at selection in breeding. That variations which might serve for the formation of new breeds must be every now and then forthcoming, is indicated by such facts as the following one, for a knowledge of which I am indebted to Mr. John Birkett. A female cat had its tail so injured by the passage of a cart-wheel over it, that her master judged it best to have her tail cut off near the root. Since then she has had two litters of kittens, and in each litter one or more of the kittens had stumps of tails, while their brothers and sisters had tails of the usual leno;th. Mr. Birkett himself saw one of the stump-tailed kittens. It is of course pos- sible that the mother had some trace of Manx blood in her, but it is not likely, and the occurrence of the phenomenon just after, and only after, the accident and amputation, seems to indicate that in this perpetuation of an accidentally deformed condition, we have an example of the origination of a new variety. * See J. Crawfonrft; Descriptive Dic- tionary of the Indian Islands, p. 255. t Its contortion is due to deformity of tlie bones of the tail. J In tlic Museum of the Royal College of Surgeons there is preserved the skele- ton of a cat, formerly belonging to the late Mr. Doubleday, the entomologist. This cat was born without any tore- limbs, yet could jump so well as to be able to jump up on a table. All the bones of the fore-limb arc entirely want- ing, save the shoulder-blades. § Mr. Bartlett assures mc he has nieisured cats' tails in the island, and found all lengths up to ten inches. II See Mr. Orton's Physiology of Breed- ing, 1855, p. 9. ■^i Sec Captain Owen's Narrative of Voyages, vol. ii. p. 180. *■* See Reugger's Siiugethiere van Para- guay, 1830, p. 212. 8 THE CAT. [CHAP. i. The direct influence of external circumstances upon different kinds of cats is worthy of note. Thus Captain Owen, R.N., (already re- ferred to), tells of a cat which, having been taken to jMombas, " under- went a complete metamorphosis," and " parted with its sandy- coloured fur " after only eight weeks' residence there. In Paraguay, again, cats seem unable to become thoroughly feral as they do in other places, and as other European animals do in Paraguay. § 7. The domestic cat begins to be ready to reproduce by the end of the first year of her life, and she is prolific to her ninth. Ilor }ouiig are carried for fifty-five or fifty-six days, and she generally has five or six 5'oung at a birth, and sometimes eight or nine. In a wild state the cat brings forth at least twice a year, but the domestic cat will do so three or four times annually. The wild cat has only four or five young in a litter. The length of life which cats attain varies with individuals, and is a point difficult satisfactorily to ascertain. It seems probable that about twelve years is its ordinary limit, but in some cases the age of eighteen years may certainly be attained under favourable circumstances. Though small quadrupeds and birds are their natural prey, cats are singularly fond of food which in a wild state they can never or but seldom attain, namely, cow's milk, and also fish. In spite also of the relative obtuseness of their sense of smell, they are said to show a marked preference for certain odours, a taste in harmony with that luxurious and ease-loving nature with which they are endowed. § 8. To know all about the history and habits of the cat, together with the peculiarities of form and colour of its various breeds, both wild and domestic, is not to have a scientific knowledge of the cat. To know the animal scientifically, Ave must be able to answer cor- rectly the question "What is a cat? " But we cannot so answer this question luilcss we know both the main facts as to the animal considered in itself absolutely, and the various leading relations in which it stands to all other creatures. " We understand a particular kind of animated being, when looking inwards we see how its parts constitute a system, and again looking outwards and around, how this system stands with regard to other types of organised existence." * No object can be understood by itself. We comprehend anything the better, the more wo know of other things distinct from but related to it. The complete natural history of any animal, in the full and proper sense of the term, is its Bioloyij. It is so because, though the study of any animal is of course mainly its zoblogij, yet fully to understand certain of its i)owers, and the conditions necessary for its existence, a side glance should be cast at the vegetable world also ; and Biology is the term which denotes the science of all living creatures — both animals and plants — and therc- * Essnys 1))' James Miutincau, Second Scries, p. 417. CHAP. I.] INTIWDUCTOBY. 9 fore embraces wltliin it both zoologi/ and hotauy. Moreover, Biology not only includes these t\YO subordinate sciences, but also the various inquiries vrliich refer to the relations which exist between their respective subject-matters. Now, in the first place, the study of the cat, as of every living creature, may bo followed up along two different lines of inquiry. One of these refers to the structure of its bod}^, the other refers to the actions which its body performs ; in other words, the animal may be considered statically or dynamically. Before, however, considering these two kinds of inquirj^ and seeing what subordinate inquiries they respectively include, it may be well to note that the cat's body is obviously a complex structure, consisting of distinct parts, which arc also obviouvsly put to different uses, and reciprocally minister one to another. Thus, for example, the limbs may more or less rapidly propel the body after prey which the eyes guide the paws to grasp and bring to the teeth and jaws by which it is divided to pass into the interior of the trunk, to be there converted by the digestive organs into nutriment, by which the limbs, the eyes, the paws, the teeth and jaws, stomach, intes- tine, &c., are themselves supported and maintained in healthy working condition. This animal's body, then, is a complex icJioIc in ichich all the parts are reclprocalhj cmh and means ; and such is the definition of " an orgais'Ism," wide as is the difference in complexity between organisms, both animal and vegetable, of very different kinds. § 9. The organism with which we are occupied, the cat's body, may, . as has been already said, be considered as to its structure and as to its actions. As to its structure it may be considered with respect to its size, shape, consistency, the number, form, and relative position of its various parts, and such study is called Anatomy. The inquiry as to its form is called Mo)pJtoIogij, and this inquiry may be directed to its larger parts and grosser structures or to its minute structure. The various parts of the cat's body, such as its tongue, ej'^es, stomach, kidneys, &c., are termed " organs," and these arc grouped together into different "sets" or "systems." Thus, e.g., we have the alimentary system of organs made up of the mouth, oesophagus, stomach, and intestine — or alimentary tube — with the various organs, liver, pancreas, &c., which are directly connected with that tube. But every organ is made up of several different animal substances, variously blended, and differing in their minute or microscopic characters. The study of such minute structure — such microscopic anatomy — is termed Histologij. Each of the various substances thus minutely differing, and which build up the organs of the body, is called a tissue, and Histology is, therefore, the science of the tissues of which every living creature may be composed. Histology enables us to understand the structure and nature of the ultimate substance or jMrenchi/nia of the body, as far as our powers of observa- tion at present extend ; but those powers are very imperfect, and 10 THE CAT. [CHAP. I. arc very far from enabling us really to understand the absolutely ultimate composition of tbc body, Anothci- science which concerns the structure of the body is Coniparaiivc Anatomy. By it the structure of the whole body or of any part of the body is compared with the bodies or corresponding parts of the bodies of other creatures. The comparative anatomy of animals is sometimes called Zootomy. The above inquiries all refer to the number, shape, arrangement, connexion and relative position of parts (whether large or minute), and to the resemblances and differences between different living creatures thus regarded. The inquiries which constitute the next set of Biological sciences, refer to the actions which the cat's body performs. Obviously the animal moves, takes food, and, if young, increases in size. The slightest observation convinces us that it has senses, feelings, and emotions, more or less similar to our own. If emaciated by starvation we see that it can by food regain its former bulk, and we may observe that triHing wounds or injuries may be repaired. Others of its actions normally result in the production of a new individual — another generation. In short the animal Ikes. These activities are, as we all know, shared by other animals, and some of them by plants also, which grow and repair certain injui'ies — replacing lost parts — and reproduce their land. 5^ 10. The term usually employed to denote the study of the bodily activities, or functions generally, is Physiology. This study is made up of various subordinate inquiries. We may consider the functions of each tissue, of each organ, and of each system of organs. Thus we have, ('.[/., the study of the actions of the system of organs which nourish and support the body : i.e., the study of the function of sustenfation. "\Ve have again the study of that system of organs Avhich serves to continue the race, i.e., the study of the function of reproduction. We shall hereafter see that the former function is performed by various organs destined respectively to receive and digest food, to distribute about the body the nutritious matter obtained from it, to breathe and to form or secrete certain products. These functions, therefore, arc those of (1) alimentation, (2) circulation, (3) resjnration and (4) secretion. But a creature, such as our t3'pe the cat, not only lives and repro- duces, it is also active, and executes a great number of apparently voluntary and other actions, and has a power of experiencing a variety of sensations. The functions then of (1) mot ion, and {"2) sensation, form other subjects of physiological inquiry. The last two functions are called t//c aninuil functiona.* The functions which minister to susteutation and reproduction, as they arc found in all living creatures, plants as well as animals, are called the verjctaticc, or vegetal, functions. * Becaiisc sensation does not exist in i spicuona i)owers of motiou are special any plant, while loconaotion ami all cun- | animal eudowiuents. CHAP. I.] INTRODUCTORY. 11 Yet anotlicr and a somcwliat peculiar study, is tlio study of (/cre/opiuciif. It is a study at once morphological and physiological. For it IS the study of the changes which tlie animal passes through in proceeding from its first condition, as a germ, to its adult stage of existence. It is, therefore, a study of form and a study of an active process both together. It is also desirable not only to note the function of each organ and set of organs, but also to consider the activity of the animal as a whole — the phi/^^iologi/ of the indkklnal or PsijcJiologi/. § 11. But we shall bo quite unable to answer the question, What is a cat ? if we do not learn the relations in which it stands to other living creatures — its position in the general scheme of things : in other words, the cat's place in nature. We must therefore compare the cat with all other living creatures ; but especially with those which resemble it the more nearly. But to do this we must first understand more or less what the general scheme of organic nature is, that is to say, we must learn something of the arrangement and classification of living beings, i.e., of the science of Taxonomij. % IS. Every animal and plant (and therefore, the cat and the cat tribe) has certain definite relations to space and time. Its geo- graphical distribution and its past history, as shown by fossil remains, also form indispensable matters of inquiry, and respectively pertain to the sciences of Organic GvograpJnj and PaI(eo)itoIogij. But every living creature has also relations with other living creatures, which may tend to destroy it or indirectly to aid it, and the various physical forces and conditions exercise their several influences upon it. The study of all these complex relations to time, space, physical forces, other organisms, and to surrounding conditions generally, constitutes the science of Hexicology.* § 13. But there is yet one more inquiry, without which any modern work on zoology would be quite incomplete, and that is a genealogical investigation, the prosecution of which pertains to the science of PJii/Iogemj. This science (assuming the truth of the doctrine of evolution)! investigates the evidence as to the various ancestral forms through which any noAV existing organism has probably passed in its descent from the most remote organisms Avhich can, with any degree of probability, be regarded as its an- cestors, AVe must then, finally, endeavour to gain what light we may as to the first origin of that form of life which has been chosen for study — in other words we must investigate the cat's probable pedigree. § 14. It appears to the writer that the study of the cat's anatomy and physiology may be best pursued by considering the functioc * «|ty — habit, state, or condition. 1" The doctrine of evolution teaches that each existing kind of animal or plant was originally derived by a natural process of generation from other animals or plants more or less different in kind from it. 12 THE CAT. [CHAP. i. of each organ and set of organs, together with their structure, and to treat of them in the following order : — I. The skeleton, hoth external and internal. II. The parts which act upon the skeleton to effect motion — the muscles. III. The organs of alimentation. IV. The organs of circulation. V. The organs of respiration and secretion. VI. The generative organs and reproduction. VII. The nervous S3^stem and organs of sense. VIII. The development of the hody. IX. Psychology. The facts of structure and function having been disposed of, we may proceed to consider the various affinities of the cat to other animals, its relations to space and time, and the question of its origin. § 16. Before, however, commencing the proposed description, it may be well to state briefly a few facts as to the chemical composition of the body. The body of the cat is chemically composed of four principal elements, namely, oxygen, hydrogen, nitrogen, and carbon, Avith small quantities of other elements — sulphur, phosphorus, chlorine, fluorine, silicon, potassium, sodium, calcium, iron, and magnesium. These elements are united together so as to form water, carbonate of lime, chlorides of sodium and potassium, sulphates and carbonates of soda and potash, phosphates and carbonates of magnesia, fiuorido of calcium, and ammonia, and they are ultimately united into very complex groups of elements, termed "organic" compounds, the study of which pertains to a special science called o'cjanic chc/iiidr//. Tl\esc very complex chemical groups of elements are called the pvo.rimatc elemeni>i of the body because they are the first component substances into which it can be dissolved when in course of being reduced to its ultimate elements. Such proximate elements arc grouped in two classes : 1. I'hosc called nitrogenous, because con- taining nitrogen, and 2, the non-nUro(jc)iot(s, because destitute of that element. Most of the component substances of the body, such, c.athetic ganglia. dl. Diaphragm. thus conveniently divisible into the bones, with their membranes — the .sh'Ho)i. ; the muscles ; the nervous system and organs of sense ; the * system of vessels, or circulatory system ; the alimentary tube, with its appendages ; the lungs and kidneys, with certain other parts, and the organs of reproduction. THE SKELETON. § 2. The word " d-ckton" is popularly taken to denote only the bones, with the caytilage or gristle which may be connected with them. It should, however, be taken to mean not only these but also the membranes, which radiating from the bones and cartilages invest every organ of the body, and finally clotlie it externally in the form oi" " skin." Such membranes penetrate the very bones themselves and support the marrow they contain ; they separate every muscle from its neighbour, and surround and lino each tube and passage in the body ; so that if every other tissue could bo dis- solved away and yet this fibrous tissue be left, we should have a coniph^tc outline model, as it were, of the cat's entire frame. ^ 3. This substance, which is, as it were, the basis of the skeleton, is formed of what is called coNNF/'rn'E tisstte, which consi.sts of a mass of delicate white hbres imbedded in a structureless material or " o-round substance ; " scattcu'cd through this are minute particles (jf protoplasm, called " corpuscles," which are more or less rounded or CHAP, ir.] THE CAT'S GENERAL FORM. 17 flattened in shape, sometimes giving off ramifying processes, which may unite with branches from neighbouring connective-tissue cor- puscles. Within the corpuscle is a round or oval nucleus, which contains one or more niic/eo/i* The structureless substance and fibres form what is called the Jiiatru of the tissue, and the cor- Fig. 3. —Connective, Adipose and Elastic Tissue. A. /c. B. Loose areolar tissue with fat cells. The fat cells. and C. Magnified view of areolar tissue treated witli acetic, acid. The wliite fibres are here no longer seen, and the yellow oi' elastic fibres witli the nuclei come into view. In Fig. B, a scries of constrictions is produced liy tlie presence of an elastic libre, which is spirally disposed about the flicre swollen and invisible) white tilires. The white fibres may be ^olou of an inch in thickness or even less. D. Fibres of yellow or elastic tissue. puscles are cells which arc thus more or less plentifully distributed within the matrix. Intermixed with the ordinary fibres may be others of a yellower colour (and with a different chemical reaction), known as " elastic fibres," or "elastic tissue." These fibres may be rendered con- spicuous under the microscope by the addition of acetic acid, which causes the white fibres to swell and become indistinct, thus revealing the existence of the unaffected yellow ones. * It may be well to remind tlie reader that the body of every animal, and there- fore of the cat, consists at first of a single " cell," or minute particle of protoplasm, and afterwards, for a time, of an aggre- gation of such cells whence all the tissues of the body are ultimately derived, and which in different degrees preserve traces of then- cellular origin. Cells commonly contain a modified internal part or parts called a nucleus or nuclei, when they are said to be "nucleated." It is very common for the nucleus to again con- tain a more minute internal particle, tei-med a ^^ nucleolus," or it may have several nucleoli. Thus, the connective- tissue corpuscles are "nucleated cells." C 18 THE CAT. [chap. II. Certain portions of connective tissue which connect adjacent bones or cartilages become very strong, and constitute the licjaments. These are flattened or rounded bands, formed of straight, parallel fibres and are very dense in structure, with corpuscles elongated in the direction of the fibres. Other fibrous structures are the membranes which closely invest the bones or cartilages, which membranes are called j^eriosteum and perichondrium respectively. These are formed of intersecting fibres, with blood-vessels, which latter are destined to supply the structures which the membranes invest, A more delicate connective^ tissue penetrates into the cavities of many bones, and is loaded with fat, forming what is known as marrow. Fat, or " adipose tissue," con- sists of round or oval vesicles (or minute bags), containing an oily matter. The vesicles are mostly from the -j'nyth. to the -iprVth of an inch in diameter. In the earliest period of its existence the /' iM£A<^^^^h /l^^^«^ Fig. 4. — Cat's Cartilage, greatly magnified. o. Fibro-cartilago. h. Hyaline caitilagc, showins the nucleated cells enclosed iu the capsules. skeleton consists entirely of connective tissue, but becomes largely transformed into bone — i.e., it ossifies — by the deposition of cal- careous salts around the blood-vessels, which advance and invade the tissue about to ossify. § 4. Cartilage, is an opaque, firm but highly elastic substance, generally of a bluish- white colour. Like connective tissue it consists of a matrix, and this contains very distinct cells. The matrix, however, is generally homogeneous. Such is Jiydlinc eartUage. Certain cartilage, however, contains fibres, and is therefore called fihro- cartilage, and if it contains elastic tissue also, it is known as nellorc fihro-cartilagc. The cells are inclosed, cither singly or in grou])s, n rounded, unbranched hollows termed capsules, the walls of which may be somewhat denser than the rest of the matrix. Cartilage CHAP. II.] THE CAT'S GENEBAL FORM. 19 does not contain blood-vessels, but can yet grow rapidly, the nuclei of the cells multiplying and the cells and corpuscles themselves enlarg- ing and dividing — the homogeneous matrix coming to occupy the intervening space as the capsules divide and separate. § 5. Bone, or osseous tissue, is a substance, two-thirds of which, in the cat, consists of mineral matter— namely, of phosphate with some carbonate of lime, and a very little fluoride^ of calcium, phos- phate of magnesia and common salt. The animal * and mineral parts arc absolutely united, since by the elimination of cither, the shape of the bone remains unaltered. Compact bono, such as that which forms the thigh-bone of the cat, exhibits on its surface a number of microscopic holes, which are the external apertures of canals, called " Haversian," which thence Fig. 5.— Sections or Cat's Leg-bone, greatly magnified. The riglit-Iiand figure shows the layers arranged concentrically arouuil the Haversian canal. The left-hand figure shows a sectiuu nearly in the jilaue of such a canal. 7i. Haversian canal. 1. Lacuna;, c. C'analiculi. enter and ramify. These holes and canals serve to admit blood- vessels. The bony substance forms concentric layers about such canals, while the layers themselves contain a number of irregular radiating spots, which are also arranged in concentric rings corre- sponding with the layers in which they lie. These spots are^inter- spaces called ''lacunaj," (and sometimes "bone corpuscles,") and their outline is so irregular because each gives off a number of minute tubular processes, termed canaUculi. The canaliculi of * This substance when boiled j'ields gelatine. Cartilage yields cliomlrin, ■which differs somewhat from gelatine in its chemical relations ; but, like it, dis- solves in hot water, and forms a jelly on cooling. Connective tissue also yields gelatine when boiled, but elastic tissue does not. The latter tissue is also (as before said) unaffected by acetic acid. c 2 20 THE CAT. [chap. II. adjacent lacunfe unite, and thus fluid can traverse every part of the bone. The Haversian canals grow larger as they proceed inwards (in such a hone as that of the thigh,) and open into still larger channels and yet wider interspaces which are called cancelli, ultimately merging into a hollow central part called the mechillari/ cnritij of the hone because it contains that deHcate fibrous tissue and fat which constitutes marrow, as already mentioned. Some bones have their entire substance replete with cavities or cancelli, and such are called cancclMed or spongy. § 6. Ossification may take place either through pre-existing carti- lage or through membrane, and in either case blood-vessels advance into the pre-existing ma- te ^^-^ he terial, and therewith that material is absorbed and disappears around them and is replaced by calcareous substance. The lacunoe are inter- spaces which have been left uncalcified owing to the presence there of certain cells. These cells have sent out radiating processes (like some of the connective-tissue colls, as already noticed,) which have also escaped the general calcification of the intercellular substance, and thus the canaliculi have been produced. Thus contents of the lacunae are truly bone- cells or corpuscles. Bone tissue therefore is, except as to its calcareous nature, very like connec- tive tissue and cartilage. The bony substance answers to the matrix of these other tissues, and the "bone cells" to their corpuscles. When the earthy matter of bone is dissolved their original cellular contents may often be detected. When a bone ossifies from cartilage, as all thick bones do, the deposit begins in the form of opaque granules of calcareous matter, which Fig. 6.— Vertical Section of surround and somctimes iuvade the cartilage Cat's Thigh-bone (Femur), capsulcs and form a dcuso and irrcgular osseous ^''Zrof'?h?'i;o?:r(Lx tlle tissue, without lacuna) or canaliculi. Spaces are KreattrochanU;rOc),aiid of tjicn formod iu this substanco by absorption. Its distal ciul (if). 1 -P ,1 11 1 A and it these spaces JargeJy accumulate, can- cellated tissue is formed. The spaces may, however, become filled with a fresh and secondary deposit of bone in concentric rings round the blood-vessels, thus forming the " compact bone " already described. When bone is formed from membrane, it assumes the compact form, with lacuna; and canaliculi, at once, and is not preceded by granular deposit. § 7. The GROWTH OF 130NE takcs place in various ways by the ossi- fication of the inner layer of the periosteum surrounding it. In long bones, which are preceded by cartilage, the ends remain for some CHAP. II.] THE CAT'S GENERAL FOBM. 21 time cartilaginous. These cartilaginous end? ossify subsequently, but long continue distinct from the median part and are called epiphijscs (Fig. 6), which only unite with the rest of the bone when the animal has attained maturity. Epiphyses are often developed at the ends of any projecting pieces of bone or " processes." A bone may thus be developed from more than one point, /. e., from several " centres of ossitication," the respective growths from which ultimately unite to form one whole. A continuation of the same process may fuse together even entire bones which have for a time remained separate and distinct. The most external layer of the skin consists of yet another substance, which is known as epiiheUal tissue, and which is very distinct in nature from connective tissue or the elastic cartilaginous or osseous modifications of connective tissue. § 8. Such are the substances or tissues of which the cat's skeleton is in its entirety composed. That skeleton is naturally divisible into two parts : (<7.) The external, peripheral skeleton, often called the Exo- SKELETON — the skin and its appendages. {h.) The internal central skeleton, often termed the Endo- SKELETON. § 9. The External Skeleton of the cat is made up of its skin, with the hair which coats it, the claws, and also the teeth. No cartilage or true bone enters into its composition. The skin of the cat, like our own skin, consists of two layers : an external layer, devoid of nerves and blood-vessels (and conse- quently of feeling), and a deeper layer, which is supplied with both nerves and blood-vessels, and is highly sensitive. The external layer is called the epidermis, the deep layer is called the dermis. At the lips the external layer visibly changes in texture, and inside the lips and mouth it becomes soft and moist, and is termed mucous membrane. This, however, is a mere modified continuation of the external skin. The superficial layer of inwardly reflected skin is termed the epithelium., which is thus but a modified epidermis, and the common term Ecteron is applied to both epidermis and epithe- lium, as the term Enderon is applied to the deeper or dermal layer {i.e., the dermis) wherever situate. § 10. The Epidermis is an epithelial tissue, and consists of numerous superimposed layers of epithelial cells, of which those near the surface are flattened into scales, while the deeper ones are more and more rounded, the deepest even assuming a vertically elongated form. As the epidermis is worn away from the surface in minute fragments, newer cells rise successively from below (to replace those lost) from a layer of structureless substance which connects the epi- dermis with the subjacent dermis. In this layer minute particles {nuclei) arise and gather round them spheroidal portions of the sub- stance itself, thus forming cells which subsequently multiply by spon- taneous division or fission, the process commencing with the division of the nucleus of each cell. The deeper strata of epidermis contain 22 TEE CAT. [chap. ii. the colouring matter of the skin, and are often considered as forming a distinct part called the refc mucosum. The superficial or older layers acquire a horny nature. The surface of the epidermis ex- hibits numerous minute orifices of sweat-glands — the pores — and, especially on the paws, numerous minute ridges. § 11. The DERMIS, or coriiun, is a form of connective tissue. Its upper surface is almost free from fibres, but beneath, these first grow abundant and then begin to leave larger and larger interspaces, till the fibrous tissue becomes what is called '^ aveolar" and so forms the substance connecting the skin with the subjacent structures, i.e., it forms that white, filmy substance which is broken through when the animal is skinned. In the deeper portion of the true skin there are curled yellow fibres of elastic tissue, and there may be some or many muscular fibres. Its outer surface is drawn out into little promi- nences or papillae arranged in close-set parallel rows (especially on the paws), which occasion the ridges above mentioned, or existing in the superimposed epidermis. Many of these papillre contain nerves and blood-vessels, the former ending in a fine coil about a minute ball or core of nucleated tissue, thus forming what are called " axile bodies," or "touch corpuscles" (Fig. 7, B). Siceat-glroKh consist of minute tubes, each opening at the surface at a " pore," whence it descends into the skin and passes through it into the loose connective or areolar tissue beneath it, where it ends in a coil surrounded by minute blood-vessels. The meshes of the loose subcutaneous tissue contain fat, which, as before mentioned, is enclosed in minute bags of membrane. It is fluid during the life of the animal, and both helps to keep the body warm (being a bad conductor of heat) and serves as a store of nutriment. Other structures called Pacinian bodies are found in some parts of the skin of the body — notably in a membrane (the mesentery) which invests part of the bowels. Each such body consists of a number of layers of membrane, with fluid interposed, and with a central space into which a nerve enters (Fig. 7, A). § 12. The CLAWS, of which there arc five to each fore-paw, and four to each hind-paw, are special thickenings of epidermis, and arc (like the outer layer of epidermis generally) horny. But the dermis is also specially modified with a view to the formation of the claws ; for at the root of each claw it forms a transverse crescentic fold over it, while beneath the claw, it is produced into a number of close-set rows of papilla) richly supplied with blood-vessels — forming what is called the matrix of the claw. From its surface, and also within the crescentic fold, fresh epidermal cells are continually formed, which rapidly become harder, and cohere to form the claw, the root part of which is soft, like the deeper layer of epidermis, with which layer it is directly continuous. The claws are placed around the terminal part of the last bone of each toe, completely investing it, and ending in a sharp i)oint. § 13. The HAIRS each consist of a root, fixed in the skin, and the shaft, or stem, which may be cyhndrical, or flattened. Each hair is CHAP. II.] THE CATS GENERAL FOBM. 23 formed, like each claw, of modified epidermal cells, but then each hair grows from a single dermal papilla only, of which it is the greatly- prolonged epidermal covering. Moreover, this dermal papilla does not stand up from the surface of the dermis, but is placed at the Fig. 7. A. Pacinian Body from Cat's Mesentery. a. Arterj'. n. Nerve. /. Pibroiis tissue. B. Touch-corpuscle. ca. Epithelium. c. Nuclei. 71. Core, into which the nerve enters. bottom of a small sac, the follicle, which is a depression in the cutis. The central part of the hair, or pith, is less dense than its rind, or cortical substance, which is formed of very long, horny cells which have coalesced. Outermost of all is the cuticle or epithelial layer, formed of very thin overlapping scales. The colouring matter is deposited within the outermost layer, and may be uniform throughout, or may be different in different parts of the same hair. Some hairs are especially slender, and have the edges of the scales of their cuticle so projecting, as to form a serrated envelope. Such hairs are " wool," and easily become entangled and adherent to- gether by their serrations, or '* felted." True hair, such as the cat's, has not the property of " felting," because its surface is smooth. Although hairs (like claws, and the epidermis generally) have no blood-vessels, yet the sudden changes which may sometimes take place in their colour, prove that nutritive modifications extend into them. Very small vessels pass into the papillse of the hairs, which are also furnished with a minute nerve, to the presence of which the pain felt when the hair is pulled out is due. 24 THE CAT. [chap, ir The root, or bulb, of cacli hair consists of the dermal sac with its enclosed papilla and the epidermal formation which lines the sac and invests the papilla. It is considerably larger than the diameter of the hair it developes. The cat's Avhiskers are simply hairs of great size, the bulbs of Avhich are well furnished with blood-vessels and nerves. Hairs are inserted obliquely into the skin, but can be made to stand up, or "on end" — as notably on the cat's tail when the animal is enraged — by means of the contraction of small muscular tibres which pass from the skin to the hair-bulbs. Fiy. S.— Transvkuwe Si.ction of a Cat';; Wiilskri;, orkatlv macnifikd. e. Cortical snbstaiioe. | m. Pitli or medulla. Certain accessory structures are called schaceous ghnids. These are minute flask-shaped bags (secreting an oily substance), which open into the upper part of the hair follicles, and so serve to lubricate the hair. New hairs are formed by the budding off of a new papilla and follicle from beside those first developed, and by the growth of a cluster of epidermic cells at the bottom of the new follicle. Neither the new nor the older follicles are really formed by an actual in- flection of the skin, though when completed they appear as if they had been so formed. Minute blood-vessels and nerves enter the roots of hairs, but do not extend beyond the dermal papilla. § 14. Such are the appendages and such is the nature of the skin which clothes the cat's body externally, and which varies in thickness in diff'erent regions, being very thin on the lips, cars, and eyelids, thicker on the back and outer sides of the limbs than on the belly, and especially thick upon the pads of the feet on which the animal walks. Of these there are seven in the fore paw, and five in the CHAP. II.] THE curs GENERAL FORM. 25 hind paw. Each pad consists of a mass of fibrous tissue and fat, and a hirgc trilobed one is placed beneath the ends of those bones on which the animal rests in walking, as represented in the figure here w m Fig. 9.— UsDEE Surface of Fore-paw. I, II, III, IV, V. Tlie five toes, I being the poUex. (1. Trilnlied pad wliirli lies beneath the distal ends of the iiietaeariial bones. "'* Pad beneath the pisifonii bone of the wri.st. m km If ^ fej Fig. 11.— Columnar ciliated Epithelial Cells, magnified 300 diameters. A miniber of eilia are seen on the flattened superficial end of each cell, which also con- tains a nucleus with a nucleolus. Fig. 10.— Under Surface of Hind-paw. II, III, IV, and V. The respective four digits. a. Pad beneath the metatarsal bones. h. Heel. given. But, as before observed, the skin does not clothe the^exterior of its body only ; at the margin of the lips it is reflected inwards, hning the mouth and continuing onto line the whole alimentary canal, and it also lines all the other passages which open on the exterior of the body. The cat's body may thus be compared with a ring-shaped air-cushion which has been very much drawn out on each surface, the central vacant space being also greatly prolonged, but contracted in diameter to represent the alimentary canal. 26 THE CAT. [chap. II. Thus tlie real body of the animal lies enclosed between the external skin and its internal reflected continuation, and answers to the en- closed interior of the ring-like air-cushion. A real " body cavity " is therefoi'c not the inside of the alimentary canal, or the inside of any other passage opening on the exterior ; all such passages being of course but so many continuations inwards of external space. A real "body cavity" would be any cavity existing enclosed between the external skin and its internal reflected continuation. This reflected skin is soft and delicate, with a moistened surface, and is called " mucous membrane.'" Such membrane lines two great sets of organs. One of these is the gastro-piiliiionari/ mucous membrane, and Imes the mouth and alimentary canal, the eyelids, ears, nostrils, cavities in the skull, and the windpipe and lungs. The other is called the rjenito-urinary, and lines the bladder and the parts con- nected with its passage outwards. § 15. Just as the external skin consists of epidermis and dermis, so its reflected portion consists of a non- vascular ejjif/ieliuni, with a sub- jacent highly vascular coriuni, which often contains much muscular fibre. Between them is the homogeneous structureless layer termed the basement membrane. The component cells of the epithelium may be elongated at right angles to the basement membrane, thus forming what is called " cohiuinar epifheliitm " (as in the stomach and intestine), or they may be rounded, forming spheroidal ejrif helium, as in the lining of the ducts of the " glands " * of the alimentary canal. Sometimes parts of the substance of epithelial cells may protrude as thread-like processes or cilia, which arc capable of performing repeatedly a whipping-like movement. A membrane consisting of such cells is called ciliated epithelium (Fig. 11), and such we shall find in certain of the cat's alimentary and respiratory organs, in the description of which f this kind of tissue will be again noticed. The coriuii) contains yellow (or elastic) as well as white fibres, and the supjily of either may be copious or scanty. Its surface may be even or very uneven. Thus it may be produced into many, often relatively large, papilla) or villi — scattered or closely set — or into ridges which may so intersect as to form polygonal pits between them. Just as the outer skin is furnished with sweat and sebaceous glands, so also mucous membrane is copiously furnished with small glands which have different functions'tin different parts ; but a generally diffused secretion, called mucus, is formed by them, which gives its name to the membrane in which its formative glands are imbedded. It is slightly alkaline, and serves to preserve the moisture of the surfaces it lubricates, as well as to protect them from the dissolving action of fluids secreted to dissolve and digest food temporarily held within cavities (the stomach, &c.) which are lined by mucous membrane. • Epitlielial cells may, as wc slial hereafter sec, take on the function manufacturing some special product "secretion." Parts which thus act are termed " glands." t See below, Chapter VI. CHAP. II.] THE GATS GENERAL FORM. The mucous membrane is connected with the suhjacent parts by HuhmucoHS areolar tissue, which is often lax, so that the mucous membrane, when not stretched, is thrown into efFaccable folds or rugm. It may also form folds which are not to be effaced by any stretching of the skin, as, e.g., on the palate (Fig. 86). The membrane lining the mouth abounds in small glands', those within the cheeks and lips being termed buccal and labial respectively. § 16. The mucous membrane of the mouth has certain calcareous appendages— the teeth — which are mainly calcifications^ of the corium, but in part are ccteronic — or calcifications of the epithelium — so that the nature of each is compound. The teeth are not only parts of the external skeleton, but are Fio. 12.— The Teeth of the Eight Side of a Cat's Mouth, seen on their Inner Surfaces. Incisors. . Caniiie.s. JJW. Premolars. iji. Two miliars. (The outer aspect of the teeth, is shown ill Fig. iO. See also Fig. 29.) j closely related to the internal skeleton also, since they are implanted in special sockets — or alveoli — provided for them in the margins of the jawbones, which margins are on that account spoken of as " alveolar." The part of each tooth which is thus implanted is its " fang." The part which appears above the surface of the niucous membrane is called the "crown," and the line of junction is the cervix, or nech. Each alveolus closely invests the fang contained within it. Most of the teeth have but a single fang, which tapers as it penetrates its alveolus ; but there may be two or three fangs to a single tooth. The teeth of the cat, when adult, should be thirty in number. Those of the two sides of each jaw are alike, but those of the upper jaw differ from those of the lower jaw. The three front teeth of each lateral half of the upper jaw are very small and simple in shape. They stand side by side, so that 28 THE CAT. [chap. n. they form (with tlieir three fellows of the opposite side) a row of six teeth arranged in the same trausversc line. Each tooth has a single, conical fang. The first, or innermost — of the three teeth of this kind on each side — is the smallest, and the outermost considerahly the largest. The innermost, wdicn quite unworn, has its crown indented by a transverse furrow, while the part anterior to the furrow is produced into three points or cusps, whereof the middle one is the largest. The next tooth is similar, save that the outer- most of the three cusps is larger and the innermost one smaller than in the tooth first described. In the third toothy there is no innermost cusp, and the outer one is much smaller, while the inner one (corresponding with the middle cusp of the two preceding teeth) is very much larger, forming almost all the crown of the tooth. This is the condition of these teeth only when quite unworn ; very soon there can only be distinguished a slight transverse pos- teriorly placed furrow, with a prominence in front of it, w^hich is more or less irregular in outline. These three teeth are called incisors, and thus there arc altogether six incisors in the upper jaw. The next tooth, which is separated from the outermost incisor by a considerable interval or diastema, is a very large, strong conical tooth called a canine, with a fang generally much thicker and larger than its crown. The crown is somewhat curved, and is sharply pointed with a strongly marked vertical groove on its outer surface, and a less marked groove on the surface which is turned towards the inside of the moutli. On its hinder margin is a more or less distinct vertical ridge. The next tooth (separated from the canine by an interspace) is a very small one, and, like the two which come behind it, is called a jvemo/ar. It has an obtuse conical crown with a single fang. The next tooth, or second premolar, is very much larger, and has two diverging fangs, one in front of the other. Its crowm is com- pressed or fiattcned from within outwards, and consists of one large triangular pointed cusp, at the base of which there is in front a small single tubercle, while, posteriorly, there are two smaU ones juxtaposed, one behind the other. The third premolar is yet larger — the largest of all the cat's teeth — and from its trenchant shape (so well adapted to cut flesh) is called the upper sectorial tooth. It has three fangs, two smaller in front (placed one within the other on the same transverse line) and one much larger, placed posteriorly. Its crown consists of three external lobes (or cusps), separated by two notches, and of one internal tubercle. Of the external cusps the first is the smallest, and the second, which is backwardly directed, is the largest. A ridge from the first and second extends inwards to meet at the inteiiial tubercle (Fig. 29), which projects downwards but little. A very slight horizontal prominence or ridge (the external cimjalnni) connects the bases of the three external cusps on the outer surface of the tooth. When this tooth is viewed from within, a sharp ridge is seen to connect the middle and hind- most of the external lobes, formiug a very cutting blade, deeply CHAP. 11.] THE CATS GENERAL FORM. 29 notched at its middle. Behind the third premolar is an exceedingly small tooth, which is called a fnic molar. It has two small fangs and a flattened crown, the greatest hreadth of which (Fig. 86) is from without inwards. The common term mo/ars is often used to denote all the teeth which arc neither incisors nor canines ; it being sometimes convenient to speak of such teeth as one whole, without distinguishing between premolars and true molars. In the lower jaw, at its anterior end, there is also a transverse row of six small incisors. The three of each half of the jaw increase in size from within outwards, as do those of the upper jaw; but they are all smaller than the upper incisors, especially the third, or posterior, one, which is not conical, like the corresponding tooth above. Then comes, with- out any interspace, a large, strong, pointed canine, so placed as (when the jaws are closed) to bite in front of the upper canine, passing up in the interspace between the upper incisors and canines. The lower canine resembles the upper canine in shape, save that it is somewhat shorter and more curved — its anterior and posterior margins being rather strongly convex and concave respectively. Next to the lower canine follow two premolars and one molar, separated however from the canine by a wide diastema. The first premolar corresponds with the second upper premolar, and bites in front of the latter. It has two fangs, while its crown (like that of its analogue above) has one large central lobe, at the base of which are two small cusps behind, with one in front. The second premolar has also two fangs, and is like its pre- decessor, save that it is larger. The lower molar is very imlike the upper one, having a more completely trenchant form than any other tooth. It is called the lower sectorial tooth. It has two fangs, whereof the anterior is much the larger. Its crown consists of two nearly equal lobes, each ending in a point, the points di- verging. At the base of the hinder side of the hinder lobe there is a minute, scarcely perceptible, indication of a posterior tubercle or "talon." On its inner side, the crown is deeply excavated between the lobes ; but externally the surface is equably convex, save that a fissure descends vertically from the apex of the notch dividing the two lobes. The adjacent edges of each lobe are very sharp, so that the tooth presents an exceedingly trenchant margin, which bites against the similarly trenchant cutting edge above described as connecting the middle and hindmost external lobes of the upper sectorial. Thus these two trenchant margins act together like two blades of a pair of ivory scissors. § 17. The teeth of the adult cat are preceded by a somewhat different set, forming its milk-teeth or deciduous dentition. There are on each side of the upper jaw three deciduous incisors, one deciduous canine and three deciduous molars, and the same on each side of the lower jaw, save that there is one deciduous molar less. There are thus twenty-six milk-teeth in all. The deciduous incisors appear when the kitten is between two and three weeks old, then follow the canines and molars, all appearing by the end of the sixth 30 THE CAT. [chap. II. week. They begin to fall out after tlie seventh month, but the lower true molar comes into its place before the deciduous molars fall out. In shape the upper incisors are like their permanent successors, save that the transverse furrow is less marked. The upper canines are smaller and less grooved than the permanent ones The first upper deciduous molar is a small, simple one-fanged tooth like its vertical suc- cessor. The second de- ciduous molar is quite unlike the tooth which replaces it, but nearly resembles the third upper premolar or sec- torial. Its outer cutting part, or blade, is three- lobod, but both the an- terior and posterior lobes are notched, and the in- ternal tubercle, which is relatively larger than in the permanent sectorial, is continued from the base of the middle lobe. There are three fangs, but the inner fang is more opposite the inter- space between the two outer fangs than is the case in the true or permanent sectorial. The third upper deciduous molar is again quite difierent from the tooth which succeeds it, while it resembles the true or tubercular molar of the upper jaw, save that its relative size is larger. The first deciduous lower molar is like the second premolar, while the second deciduous molar is like the inferior sectorial, with a relatively smaller anterior lobe and a much larger posterior tubercle, or talon, which is notched so as to form two small posterior tubercles at the base behind the posterior and greater lobe. § 18. Such being the dentition {i.e. tooth-furniture) of the cat, it may be conveniently expressed by the following symbols Fi^. 13.— The Cat's Milk Dentition, enlarged. Below, the true molar is seen much advanced, and soon to rise behind the second lower deciduous molar. In the upper jaw the jierniatient ui)per .sectorial is secii in an advanced state of development above the third deciduous molar. If PMf Uj for the second, or permanent dentition. means " three incisors, above and below, on each side of the jaws ; " c-j- means similarly, " one canine on each side of each jaw ; " pm^ means " three premolars on each side of the upper jaw and two on each side of the lower jaw ; " and M-j- means " one true molar both above and below on each side." Similarly, the symbols di}, nc|, DZkif for the milk dentition, refer in the same manner to the deciduous incisors, canines, and molars respectively. It need hardly be added that each tooth attains its full develop- ment within a limited time, after which it grows no more, and no third development ever replaces the fall of a tooth of the permanent dentition. CHAP. II.] THE CATS GENERAL FORM. 31 § 19. The SUBSTANCE of cacli tooth consists of a dense tissue of three kinds, called (1) Dentine, (2) Enamel, and (3) Cement, investing a small soft and sensitive mass called the pulp. The great hody of each tooth is formed of dentine, and it is this which immediately surrounds the pulp. The cement coats the fang of each tooth only, while its crown is invested with a covering of enamel, which is the hardest kind of tooth substance. The pulp consists of areolar tissue with cells and nuclei, and is in fact a modified portion of the corium — a large dermal papilla. It is highly vascular, and supplied with a nerve also. Dentine is an animal substance impregnated with 72 per cent, of earthy matter, of which nearly 67 per cent, is phosphate of lime. V\s. 14.— Tooth Substances. A. Vertical section of secoiul upper premolar. B. Horizontal section of riglit upper sectorial. d. Dentine, c. Cement, e. Enamel. IK. Pulp cavityi Instead, however, of presenting the lacunae and canaliculi of ordinary osseous tissue, dentine only exhibits a number (but an enormous number) of very minute and very close-set tubes, which radiate fi'om the wall of the pulp cavity on every side and with slight undulations ; they become smaller towards the outer part of each tooth, while at their inner ends their diameter is about the t-Vo of an inch. Each tube, as it proceeds, gives off exceedingly minute branches, which appear to anastomose, and the tubules end distally by forming loops or by opening into minute cavities (dentinal cells) which are disposed around the dentine close to its surface, forming what is called its granular layer. The greater part of the earthy matter is contained in the matrix, between the tubules, which do not in fact proceed from the j)ulp, but advance upon it, the outermost layer being that first calcified. The Cement closely resembles bone, since it contains both lacunae 32 THE GAT. [chap. II. and canaliciili. It is tlilnnest towards the cervix of cacli tooth, and thickens towards the apex of each fang, and there it may even contain vascular canals like the Haversian canals of bone tissue.* The Enamel is so mineralized a structure that it only contains about 3 1 per cent, of animal matter, while it has 90 per cent, of phosphate of lime. It consists of a multitude of slender, solid, undulating, hexagonal rods, closely adjusted to each other, and about 5-yVn of an inch in diameter. Each rod is attached by one end to a minute depression of the surface of the dentine, and thence extends outwards, its distal part being at right angles to the external surface of the enamel. § 20. We have seen that hair and claws are epidermic dermal appendages, but teeth are appendages of the dermis. They are not altogether so, however; for though the dentine is formed by ossification of a process of the cerium, and cement by calcifi- cation of the connective tissue surrounding that papilla, yet the enamel has a different, and indeed an epidermal origin. It is formed from a depression of the epithelium of the gum, which dips in till it becomes applied to the apex of the rising dermal papilla, which last is destined, by its calcification, to form the bulk of the tooth. Having thus applied itself to invest the crown of the nascent tooth, it calcifies and so be- comes the enamel. Thus each tooth has a double nature. By its dentine and cement it is dermal, but its enamel is a modification of the epi- dermis. Each permanent tooth takes its origin in a cavity of the jaw, placed just behind the milk-tooth it is destined to succeed. A little process from the inflected epi- thelium (or " enamel organ ") which forms the enamel of the milk-tooth, is given off to invest the minute papilla which is to grow into the permanent tooth. As the new tooth is formed it rises in the gum, the space inter- vening between it and its successor becoming richly supplied with blood-vessels. The substance of the milk-tooth then becomes Fig. 15. — Thin Si:ction oftiik Enamel and a i-Ain' or the nCNTINE, 300 DIAMKIKUS. a. External .surfaco. h. Tlio rods or ssolid, six-sided ])nsiii.s. (/. Tuliuli ol'tlu! (U'litiiic. c. Clefts wldcli occasionally exist ill the ileei> part of thu ciuiinel. * A sub.staiicc called odco-dcnlinc i.s soniutiincs jirodiiccil by tho o.s.sificatiou of thu pulp itsuir. It lias vascular quasi Haversiau canals, surrounded ■ by con- centric laniellie, and is so far like bone. On tlic other hand, tubuli radiate from these canals, which tubuli are larger than the canaliculi of bone. CHAP. II.] THE CAT'S GENERAL FORM. 33 rapidly absorbed away by tlio aid of the blood-vessels — first the cement, then the dentine, and even part of the enamel — till what is left becomes loosened and falls out. As the new tooth rises into the place of its predecessor, the bone of the jaw becomes simultaneously modified by absorption and redeposition, so as accurately to fit its fang — a strildng example of that wonderful power of harmonious and spontaneous modification which pervades the living body. CHAPTER III. THE SKELETON OF THE HEAD AND TRUNK. § 1. The internal skeleton, or endoskeleton, of the cat is made up of numerous bones with cartilages and fibrous structures. The number and nature of the parts vary with age. In the earlier stages of existence the cat has no bones at all, but ossification having once begun, goes on for a time energetically till maturity is attained ; and, indeed, to a certain extent ossification goes on throughout life. In this way it comes about that parts which are membranous in the kitten, or cartilaginous in the young cat, become bony in the full-grown animal. A continuation of the same process tends to unite bones which at their first appearance were separate. This process of union of bone with bone is called anchylosis. The hard parts of the internal skeleton being those which act as a framework suj)port the body, form points of attachment for the muscles which move it ; the muscles employing the difierent bones like so many levers or fulcra, as the case may be. The great majority of bones being thus intended to move one upon another, certain parts of their surfaces are specially modified for mutual adjustment and motion, i.e. the contiguous surfaces of such movable bones form joints. These modifications will appear, as the forms of the bones are successively noticed ; but the nature and mechanism of all the different kinds of joint will be more conveniently considered together after the skeleton has been described, immediately before studying the moving organs themselves. § 2. The parts which compose the internal skeleton may obviously be grouped into two divisions : — {a). The skeleton of the head, trunk, and tail, which is called the AXIAL skeleton. {h). The skeleton of the limbs, which is called the ArPENni- CULAR SKELETON, the Hmbs being regarded as appendages of the axial i)art of the body. THE AXIAL SKELETON. The axial skeleton is further conveniently divisible into the skeleton of the back, or spinal skeleton, — consisting of what is CHAP, in.] SKELETON OF THE HEAD AND TRUNK. 35 familiarly known as the backbone, ribs and breastbone — and the skeleton of tbe head, or cranial sJiekton. THE SPINAL SKELETON. As has been said, this consists of the backbone, together with certain arches, the ribs, which extend from each side of a certain portion of the backbone downwards to or towards the breastbone or sternum. § 3. The backbone, or, as it is often called, the sjnne or spinal column, consists of a number of small bones placed one behind the other, like a series of counters. Each of these small bones is called a VERTEBRA, and (with certain few exceptions, to be considered later) consists of a bony arch projecting upwards from a solid disk — the counter-like portion of the bone. Each whole vertebra may thus be described as a ring much expanded at one part, which is ihQ lower part, and with certain bony prominences, which stand out from the bony ring in various directions. The vertebra} being, as has been said, placed one behind or in front of the other, their juxtaposed rings together form a long horizontal canal (ring being placed opposite ring), which is called the rcrtchml canal. It is also called the neural canal, because it is destined to contain and protect the central part of the nervous system of the trunk, namely the spinal cord — or, as it is popularly termed, the spinal marrow. The thickened inferior parts of the vertebrae are also adjusted one in front of another, and by their juxtaposition form a solid but flexible horizontal rod. § 4. The thickened inferior part of each vertebra is called its "body," or centrum (see Fig. 16) ; the ring of the vertebra springing from the centrum is called, as before said, the neural arch. Each lateral half of the neural arch consists of two parts : an inferior rounded part called the pedicle, and a superior broad and flat portion called the neural lamina. The various bony prominences of the vertebrae are termed '' 2)rocesses" and at least three kinds of such processes are very generally present. The first of these is the process which projects upwards from the junction of the neural laminae at the summit of the neural arch. This is the spinous process, neural spine, or neuropophysis. From the junction of each lamina with its pedicle another process, ending bluntly, juts outwards and upwards : this is called the transverse process. Other processes which project more or less forwards and backwards from the outer part of each lamina to meet corresponding processes of adjacent vertebrae, are termed articular processes or zygapophyses. Those projecting forwards have a smooth articular surface, which looks mainly upwards, and are called anterior articular processes, or prezyrjapophyses. D 2 36 THE CAT. [chap. in. Those projecting backwards have a smooth articular suritxce, which looks mainly downwards, and are called posterior articular processes, or posfzj/gcqJOjjJ/yses. The anterior margin of each pedicle is somewhat concave, while its posterior margin is generally more so. In this way, the vertebrae being naturally juxtaposed, the adjoined concavities, or notches, of two adjacent vertebra?, constitute a rounded opening termed an hiicrvcytehml fornmen. These foramina communicate with the neural canal, and enable nerves and vessels to pass thence outwards. The adjacent surfoces of the bodies of the vertebrae are nearly flat, and arc connected together by the intervention of a fibrous pad — the interi'crtehr(d suhsfancc — which "will be described later, amongst the ligaments. The vertebrae are composed of cancellous bony tissue invested by compact bone. The latter is most abundant on the arch and processes. The body of each vertebra is almost entu-ely composed of spongy substance traversed by canals for veins. Such is the general condition of most of the vertebrae, but in some of them certain of their parts and processes are wanting, while in others there are additional parts and processes. § 5. The vertebras are divisible into five difierent categories. (See Fig. 23, c, d, /, .s, and ca). First come those of the neck, which are termed ccrcical. They are seven in number. Secondly, those of the back, which have the ribs attached to them and are called dorsal. Of these there are thirteen. Thirdly, we find certain large vertebriis which do not bear ribs : these are situate behind the dorsal vertebrae and are called lumbar. There are seven of them. All the above are termed " true vertebrae," because they do not become anchylosed together, but remain connected only by ligaments and by the intervertebral substances. Behind these true vertebrae come three which are called " false," and which sooner or later anchylose together to form a bony mass. This mass, termed the sacrnni, comes immediately behind the lumbar vertebra\, and part of it affords attachment on each side to one of the haunch, or hip, bones. The sacral vertebrae thus anchy- lose together to constitute the sacrum. The rest of the vertebrae arc called caudal, and form a series of some twenty bones which decrease, gradually, backwards as regards their complexit}^ of structure, but increase in length to about the tenth, and then again become successively shorter, as well as simpler, to the end of the tail. ^ 6. Of the vertebrae, the doiisal, as the simplest of those in front of the tail, may first be selected for description, the fifth dorsal being taken as the type. The centrum of this vertebra (c) is about three quarters as deep from above do^-nwards as it is broad from side to side, its length (from before backwards) being about equal to its breadth. Its upper surface is more or less flat- tened. Its under surface is strongly convex from side to side, CHAP. III.] SKELETON OF THE HEAD AND TRUNK. 37 and somewhat concave from "before backwards. Its anterior and posterior surfaces are flattened, but tbe former is somewhat convex and the latter somewhat concave. The pedicles have their anterior notches very shallow, but their posterior ones very deep. The neural laminae are almost as wide from before backwards as from side to side, and the neural arch overlaps that of the vertebra Th' 1(5. — Fifth Dorsai. Vi;rtebra. A. The vertebra seeu on its right side. B. Anteridr view. C. Posterior view. h. Small tubercle. c. Centrum. d. Tubercular .surftice. p. Capitular surfaces. *-. Neural spine. t. Transverse process. X. Anterior zygajiophysi-s. 5. Posterior zygapopliy.sis. next behind. The spinous process is very elongated, pointed and inclined upwards and backwards. The zygapophyses are almost horizontal, the anterior ones (Z) looking upwards and slightly forwards and outwards ; the posterior ones (5) looking downwards and slightly backwards and inwards. The transverse process (t) projects outwards from nearly the summit of each pedicle, almost entirely hiding the anterior zyg- apophyses when the vertebra is seen in profile. A little tubercle {b) projects from the upper surface of the distal part of the transverse process.* Like almost all the other dorsal vertebrae, the fifth dorsal exhibits certain articular surfaces which are called costal, because they serve for the attachments of the ribs. There are two kinds of such surfaces. One kind, attached to the centrum, are called capitular, because they articulate with the heads, or the capitula, of the ribs. The other kind, attached to the transverse processes, are called * "Distal" and " proximal " are two ; fZtsteZ part of a limb ; that part of a limb words respectively expressing remoteness which joins the body is the 2^'''oximnl from and nearness to a centre or point of part. The tip of the tail is " distal ; " attachment. Thus, c.rj. the paw is the its root is "proximal." 38 THE CAT. [chap. hi. fuhercular, because ttey articulate Avith the tubercles of tbe ribs. The tubercular surface {d} is a smooth, oval surface, slightly pro- longed from before back-wards, and placed one beneath the distal end of each transverse process and giving attachment to the tubercle of the fifth rib. The capitular surfaces (p, p) are two in number on each side. One is placed at the junction of the pedicle with the centrum in front ; it is smooth, and looks forwards and outwards. _ The other is placed just beneath the posterior notch of the pedicle ; it is smooth, and looks so almost directly backwards and so very Httle outwards as to form part (the outer and upper angle) of the posterior surface of the centrum. The anterior capitular surface concurs with the posterior capitular surface of the fourth vertebra to form with it an articular cavity for the head of the fifth rib. Similarly its posterior capitular surface concurs with the anterior capitular surface of the sixth vertebra to form an articular cavity for the head of the sixth rib. The ring formed by the neural arch and centrum is oval, trans- versely extended, and somewhat flattened below. The eleventh, twelfth and thirteenth dorsal vertebra) have each but a single capitular surface on each side — namely, an anterior one. The first dorsal has an anterior capitular surface large enough to receive the whole head of the first rib. The eleventh, twelfth and thirteenth vertebra) have no tubercular surface. The first two dorsal vertebra) have the front surface of the centrum strongly convex and looking much downwards, and its hinder surface concave and looking much upwards. The tubercular surface also is strongly concave. As we proceed from before backwards, through the series of dorsal vertebra) to the tenth, the transverse processes come to extend less outwards and to be more expanded from before backwards at their distal ends ; the postzygapophyses become situated further backwards, and the neural spines (counting, at least, from the seventh,) also become shorter. The tenth dorsal vertebra has its transverse process very much extended from before backwards (Fig, 17,^°). Its posterior end projects backwards more than in any preceding vertebra, reaching to, or even beyond, the anterior margin of the pedicle of the eleventh vertebra. The postzygapophyses look as much outwards as down- wards, or even mainly outwards. In the eleventh dorsal vertebra the neural spine projects more or less forwards (Fig. 17, ^^ *'), instead of backwards, abutting against that of the tenth vertebra, which it may, or may not, slightly exceed in length. It has no transverse process, but there arc two conspicuous processes on each side, which evidently answer to the processes (one at each end) which terminate the transverse process of the tenth vertebra, but which, in the eleventh vertebra, are quite separated the one from the other. The anterior process (Fig. 17, ^^ '"), which projects forwards. CHAP. III.] SKELETON OF TEE HEAD AND TRUNK. 39 upwards and outwards, outside tlic prezygapopliysis, is termed the mammillary process, or Metajyophysis. The posterior process {a), which projects backwards as much as any other part of the vertebra, is called the accessory process, or AnapopJujsis. The prezygapophyses look almost entirely inwards, while the postzygapophyses (5) look almost entirely outwards. The twelfth and thirteenth dorsal vertebra) are like the eleventh, but their anapophyses are stouter and their neural spines are larger and project more forward. § 7. The seven lumbar vertebrje are larger and more massive than the dorsal vertebrre, and increase in size as we proceed back- wards as far as the sixth lumbar (see Fig. 23). Selecting the fifth for comparison with the fifth dorsal, we find its centrum broader in proportion to its depth, about twice as long, less convex transversely below, and with a slight median ridge, called Jiijpcqjophysial* running from before backwards, along its under surface. The neural lamina and pedicel are much longer, and the latter, though deeply notched behind, is scarcely at all so in front. The neural spine is very much 1 , 1 1 J. 1 n 1 i.* 1 Fig. 17.— Side View of the shorter, absoiuteiy as well as relatively. tenth and eleventh vertebk^. It is elongated from before backwards, •slightly separated. and inclines forwards instead of back- n! Eleventh vertebra. wards, thus agreeing with the last S; TuSlar process. three dorsal vertebrae. "«■ Metapophysis. rr,, 1 i.1 • 1 7 '^- Psrt of transverse process ine zygapopnyses are tnicKer, and which conceals from view their articular surfaces are differently j,. capituTarproSssf' shaped from those of the dorsal vertebrae. t; ?T'^.^ ^i'"^''- , . *; 1 1 • 1 i> • /;. Anterior zygapophysis. ii.ach prezygapophysiai SUriace is :■>. Posterior zygapophysis. concave, and looks inwards as well as upwards. The postzygapophysial surfaces are convex, and look outwards as well as downwards, being embraced by the pre- zygapophyses of the vertebra next behind. The transverse processes are very much longer than those of the dorsal vertebrae, and project very much forwards and strongly downwards as well as slightly outwards. There are no capitular or tubercular surfaces, the lumbar vertebrae not bearing ribs. The metapophyses and anapophyses are large and conspicuous, though not more so than in the last dorsal vertebra. The neural canal is larger and more quadrangular than in the dorsal region. The more anterior lumbar vertebra3 closely resemble the more * Because it represents a certain process, present in many other animals, which is called a hypapophysis. 40 THE CAT. [chap. III. posterior dorsal vertebrae, the first lumbar being quite like the ast dorsal, except that it Has no capitular surface, but, in its place, a short forwardly extending transverse process, and^ that the met- apophyses are somewhat larger. As we proceed backwards through the series of lumbar vertebrae, Fig. IS.— Fifth Lumbar Vkrtebra. a. Anapophysis. c. Centrnni. 'M. iMetapophysis. '/i. Neural luinina. s. Neural spine. 1. Transverse process. ~. Prezj-gapopliysis. 3. Postzj-gapophysis. the anapophysis decreases, so that in the sixth lumbar there is but a minute rudiment of such a process. The metapophysis is at its maximum in the fourth lumbar vertebra, but is large even in the last. The neural spine is longest at the fourth. The transverse process increases rapidly from the first lumbar vertebra to the fourth, and is slightly longer in the fifth and sixth lumbar vertebra:. The zygapophyses continue to bo directed as in the fifth lumbar vertebra, except that the postzygapophyscs of the seventh look once again more downwards. The centrum of the seventh lumbar vertebra is not longer than is that of the first, and the same is the case with the neural arch. § 8. Having noted the characters of the -vertebra' next behind the dorsal ones, we may advance to those in fi-ont of them. Of the seven cervical -vERXEBR.ii; the first two are sufficiently exceptional to demand separate notice. The other cervicals are very much alOce, but the fifth may be selected for comparison with the fifth dorsal vertebra. Its centrum is relatively wider from side to side and narrower CHAP. III.] SKELETON OF THE HEAD AND TRUNK. 41 from above downwards than in cither the dorsal or the lumbar vertebrix!. The front surface of the centrum is convex, and looks much doxsTiwards as well as forwards, and its hinder surface is concave and looks much iipwards as well as backwards. The pedicle is narrow from before backwards, and its anterior notch is as marked as its posterior one ; but this appearance is mainly due to the projection forwards of the prezygapophysis (s). The neural lamina) are much flattened, and are broadened transversely like the centra. The spinous process is short, small, and projects somewhat forwards. The zygapophyses are large and flat. The articular surface of each prezygapophj'sis looks upwards, forwards, and Fi^'. 10. — Fifth Cervicat, Vertebra. A. Side view. B. Front view. C. Back view, c. Centrum. s. Neivral sjiine. t. Transverse process. V. Vertebral canal. -. Prezygapoiiliysis. 3. Postzygapophysis. slightly inwards. Its outer surface presents a roughened pro- minence. The articular surface of each postzygapophysis looks downwards, backwards and slightly outwards. There is a large plate-like transverse process {f) which springs from two roots. One of these descends from the front of the side of the pedicle, the other projects from the centrum, just at the place where the capitular articular surface of a dorsal vertebra is jjlaced, and so may be called a " capitular process." These two short roots unite and enclose a space (^?) called the rcrtehral canal, because it is traversed by the vertebral artery. Thus this vertebra may be said to have " perforated transverse processes." Beyond the junction of its two roots the transverse process expands into an irregularly quadrilateral plate, one surface of which looks outwards, upwards, and shghtly forwards, while the other looks inwards, downwards, and slightly backwards. From near the hinder angle of this plate a process, somewhat like an anapophysis, projects upwards and backwards, so that the plate may be said, at this part, to slightly bifurcate. The other cervical vertebra (except the first two) more or less 42 TEE CAT. [chap. III. closely resemble the fifth cervical. The seventh, however, has a longer spinous process (like that of a dorsal vertebra), and no vertebral canal — only that part of the transverse process being developed, vrhich corresponds with root above the vertebral canal and with the anapophysis-like process of the transverse process of the fifth vertebra. These parts, therefore, may be taken to represent the B Fis. 20.— The Axis Vertkbra. A. B. Side view. Front view. C. Back view. D. Dorsal view. E. Ventral view. al. Anterior articular surface. c. Posterior articular surface of ccntniin. 0. Odontoiil process. .., about fifteen or sixteen times as long as broad, but its width varies slightly at intervals throughout its ■whole extent. The sternum is connected on each side with the cartilages {ca) of the first nine ribs, one cartilage on each side being attached to each successive pair of sternebra) at their junction, as well as to the side of the manubrium and the hinder end of the seventh sternebra. The first sternebra, which ends anteriorly in a laterally compressed pointed process {p), is called the manuhrium, or presternum, and extends forwards in front of the insertion of the cartilage of the first rib. The second part (or the bod// of the sternum) is made up of all the other six sternebra) together. The third part (x) is the xiphoid, or ensiform, process, which varies in shape in different individuals, and long remains cartilaginous. The hinder end of the manubrium affords a surface for the attachment of the second costal cartilage. The first sternebra of the hod// completes the surface for the second rib. The notches for the third, fourth, fifth, sixth and seventh ribs are situated at the lines of junction of the sterncbrse of the body of the sternum — as before mentioned. The notches for the eighth and ninth rib cartilages are placed close together at the hinder end of the seventh sternebra (see below, Fig. 78, B,/'). This xiphoid cartilage projects freely backwards, tapering towards its generally more or less expanded and fan-shaped distal end (c). § 16. The RIBS {costce) are long, slender, curved bones, which extend obliquely downwards from the spinal column, and end below in cartilaginous prolongations called costal cartilages. Some of these join the sternum by their cartilages (Fig. 24, ca), and others do not. There are thirteen libs on each side. The nine anterior ribs on each side are called " true ribs," and join the sternum by their cartilages. The four hinder ribs do not join the sternum, and arc therefore called " false ribs." The ribs generally are curved at first (starting from their attachments to the vertebral centra) out- wards and a little upwards, then backwards, and outwards and much downwards. Taldug the sixth rih as a type, the following points may be noted : its proximal or upper and inner end is thickened, and is called the capitiiluni, or head, of the rib (c), and it is this which joins the capitular surfaces of the fifth and sixth dorsal vcrtebne by two corresponding oblique articular surfaces, with a ridge between. The i)art of the rib next to the head is termed the neck (ii), and this short portion terminates at what is called the tuhcrcuhtm (f), or tubercle of the rib. This is a rounded prominence on the hinder border of the bone. It looks upwards, and presents a smooth surface for articulation with the transverse process of the sixth dorsal vertebra ; outside this smooth prominence is a rough surface of bone. The neck of the rib is narrower than is the fii'st part CHAP, in.] SKELETON OF THE IJEAD AND TRUNK. 51 of tlic^ "body," — the "body" of the rib being all that portion which is distal to, or beyond, the tubercle. This body (b) is somewhat flattened, from before backwards at its upper part, and slightly expanded, in the same direction at its distal end, the in- tervening part being nearly cylindrical. It exhibits a faint indication of a groove running along its hinder side, especially at the upper part of its body. A little beyond the tubercle the bone makes a sudden bend downw^ards (a). This part is termed the angle, and it is behind it that the groove just mentioned is most distinctly developed, while in front it exhibits a roughened line for muscular attachment. The distal end of the bone is hollowed out into un oval pit {p), and into this the sixth costal cartilage is inserted. rig. 2J.— Side View of Ribs. A. First rib. B. Si.\lhril.. C. Tliirteeutli rib. «. Anglo. h. Body. c. Ciiiiitulum. n. Neck. p. I'it for costal cartilage. (. Tuberculuui. The other true ribs differ but slightly from the sixth, except as to length, which decreases as we pass forwards or backwards from the ninth, wdiich is the longest rib. The first rib is the broadest of all (Fig. 25, A), especially towards its proximal end. Its capitulum has but one articular surface. The " angle " about coincides in position with the tuberculuin. The false ribs decrease in length backwards, but the last rib is longer than even the fourth true rib. The three foremost false ribs (the tenth, eleventh and twelfth) are united together by their costal cartilages, but the thirteenth rib ends freely, and is thence termed a floathnj rib. The last rib (Fig. 25, C), has but a minute rudiment of a tuberculum or none, and the capitula of the last three ribs have each but one articular surface. 52 THE CAT. [CHAP. in. The a))r/ks of tlic ribs become more and more distant from the tubercula as we pass backwards to the eleventh rib. The thirteenth exhibits no angle. § 17. The COSTAL CAUTILAGES (Fig. 24, ca), differ much as to length, connexion, shape and direction. The tenth is tlie longest, and tlience the length decreases as we pass either forwards or backwards through tlio scries. The first nine join the sternum. That of the tenth rib joins the costal cartilage of the ninth rib, and similarly tlie eleventh and twelfth costal cartilages unite distally with the lower border of the costal cartilage next in front. The thirteenth costal cartilage ends freely. The first costal cartilage is the broadest, and thence they gradually narrow backwards. The last cartilage is pointed at its distal end. The upper (proximal) end of each costal cartilage is convex, and fits into the distal con- cavity of its rib. As to direction, the cartilages pass at first backwards, then downwards, curving distally forwards from the fourth to the seventh. The first cartilage has a nearly horizontally forward direction, while the last extends downwards and backwards. § 18. The THORAX AS A WHOLE fomis a long, transversely narrow, conical case, with a small aperture in front and a wide oblique opening behind. It is considerably deeper from above downwards than it is wide from side to side. The variation in its dimension, which shows itself as we proceed, from before backwards through the thorax, is produced by the corresponding variation in the length of the ribs and in their curvature. The anterior opening is bounded by the first pair of ribs, the first dorsal vertebra and the manubrium. The posterior opening is bounded by the xiphoid process, the cartilages of the four hindmost ribs, the body of the thirteenth rib and the thirteenth dorsal vertebra. § 19. {Such being the structure of the bony and cartilaginous parts which make up the spinal portion of the axial skeleton, we have next to consider the fibrous bands, or ligaiments, which hold together the bones and cartilages already described. The substance inter- posed between each pair of true vertebra is an elastic body termed an i)ifcrfcrtcbnil (//•sc. Each such disc is made up of concentric lamella) (Fig. 26, ./'), of fibro-cartilaginous and fibrous tissue, surrounding a soft central por- tion if/), which is very elastic (projecting beyond the general level of the disc when pressure is removed) and contains immerous nu- cleated corpuscles like those of cartilage. The surface of each centrum is covered (except towards its cir- cumference) with a thin layer of cartilage, and it is to it that the intervertebral discs are attached. These discs form so many elastic pads, and one such is placed between each pair of presacral vertebra), except between the atlas and the axis. A strong band of fibres, called the roitral coiumon /if/nijioif, extends along the ventral surface of the vertebral bodies. It is thickest where it passes over the middle of the centra than elsewhere, and CHAP. III.] iiKHLETON OF THE HEAD AND TRUNK. 53 thus tends, by filling up depressions, to render tlic surface of tlio vertebral column more even. Another band of fibres, called the dorsal common ligament, passes backwards within the neural canal along its ventral surface from the skull backwards. Eacli pair of articulating z3^gapopbyses is surrounded and enclosed by a fibrous bag, the fibres passing from one zygapopbysis to tlie other. Such a surrounding and enclosing membrane is termed a capsular Urjament. Enclosed within the capsular ligament is a Fi£'. 20. — Intervertebral Disc;. A. Surface view enlarged. B. Section tlirougli two di.ses. /. IjauMjlUt. g. Scift pentral portion. ■(. lutersxiinous ligaments. membrane which secretes an albuminous fluid termed synovia. Membranes of the kind are therefore termed synovial, and are placed between hard parts which are destined to move one on the other. Synovial membranes will be more fidly noticed in the descrip- tion of the different kinds of joints at the end of the next chapter. Certain Hgaments with much yellow elastic tissue, called the liga- menta suhjiava, pass between the neural lamina, being attached to the umer or ventral surface on one neural lamina and thence passing backwards to the anterior margin of the neural lamina next behind. They are thus best seen when the neural arches are removed and viewed on their ventral aspect. 54 THE CAT. [CHAP. in. Adjacent spinous processes arc also connected together by mem- branes (Fig. 26, B, i), called inferspinous Vtfjaments. Narrow bundles of fibres, forming a sort of cord, pass backwards along the spinous processes. These are the supra sjjinous ligaments. A forward prolongation of these supraspinous ligaments is termed the lifjanicntum micJicB, and passes from the cervical neural spines to the slcull. Adjacent transverse processes are also connected together by fibrous bands termed the inter-transverse ligaments. These are largest in the lumbar region, while they are rudimentary in the vertebra3 of the neck. The mohiUty of the spinal column is different in different regions, being greatest of course in the tail (save in some breeds), which can be bent freely in any direction owing to the absence of interlocking bony processes, except in the most anterior caudal vertebrae. After the sacrum, the mobility is least in the dorsal region, on account of the overlapping of the neural laminao. In the cervical region there is much mobility, even apart from the axis and atlas, the motions of which will be treated of separately. Lateral bending and rotation are variously limited by the direction of the articular surfaces of the zygapophyscs, which, as has been noted, arc different in different regions. § 20. The AXIS and atlas articulate together in a manner altogether peculiar. The atlas (with the head to which it is attached) can turn round to a great extent in either direction upon the odon- toid process as on a pivot, being retained in place by ligaments. Synovial membranes are interposed between tlie articular surfaces of the atlas and axis, which surfaces are kept in apposition by capsular ligaments. The odontoid process is kept in place by the transverse ligament of the atlas, which extends across above that process and between the internal margins of the anterior articular surfaces of the atlas. From the midst of this transverse ligament two bimdles of fibres are given off" in opposite directions, one bundle passing backwards to the centrum of the axis, the other forwards to the skull, thus giving rise to the figure of a cross. A synovial membrane is placed both above and below the odontoid process, corresponding with the two smooth surfaces which have already been noted as existing upon it. Three ligaments pass forwards from the odontoid process to the skull, i.e., one from its tip to the margin of the opening of the skull in front, and two others (called alar or cJieelc ligaments) from the sides of the summit of the process to the inside of the condyles of the skull. These crucial and odontoid ligaments arc covered over above and sheltered by another called the occipito-axial ligament, which is ])laced in the ventral part of the neural canal between them and the most anterior part of the dorsal common ligament. It passes up from the centrum of the axis to the inside of the floor of the skull. CHAP. III.] SKELETON OF THE HEAD AND TRUNK, 55 Another ligament, the rentral occipifo-atlantcd ligament, passes from the front ventral border of the atlas forwards to the adjacent part of the skull, and similarly the ventral atlanto-axial ligament connects the ventral arch of the atlas with the centrum of the axis. Certain other ligaments connect together the neural arch of the atlas with that of the axis and with the skull. The first of these is the dorsal atlanto-axial ligament, connecting the neural arches of the axis and atlas. Another is the dorsal oecipito-edlantal ligament (Fig. 27, ^), which connects the neural arch of the atlas with the adjacent margin of the posterior aperture of the cranium. A third ligament, the transverse (dlanio-occipital (^), passes outwards upwards and forwards on each side from the neural arch of the atlas to the inner side of the adjacent occipital condyle. Yet another liga- ment may he called interspinous. It connects the neural sj)ine of the axis with the middle of the dorsum of the neural arch of the atlas. ^ 21. As to the ribs, a ligament, named "s^^/Zr/?'^," passes, in a Fig. 27.— Lic.VMENTs OF Atlas and Axis. 1. Dorsal ocpipito-atLmtal ligament. 2. Dorsal atlanto-axial ligament. 3. IiiterBpinou.s ligament. 4. Rertus lateralis mnsclc. 5. Tran.sverse atlanto-occipital ligament. so. Suiira-oceipital, radiating manner, from the ventral surface of the head of each rib on to the intervertebral substance opposite to it, and on to the bodies of the two adjacent vertebrse. Another ligament, named inter-articular, passes transversely from that ridge on the head of the rib which divides its two articular surfaces, to the intervertebral substance. This ligament of course does not exist in the articulations of the first, eleventh, twelfth, and thirteenth ribs, which have each but one articular surface. The ribs, except the first and the last three, are also connected with the transverse processes, each by certain other ligaments ; but none of these attachments prevent each rib from performing a slight movement backwards and forwards upon its vertebral attachment, as well as a certain movement of rotation. The pieces of the sternum are connected by cartilage, and bound 66 THE CAT. [chap. III. together both in front and behind by ligamentous fibres, and such fibres surround the articulations of the costal cartilages with the sternum, and thence radiate over the latter both dorsally and ventrally. The various articulations of the ribs with the vertebrae and of the costal cartilages with the sternum, are furnished with synovial membranes. Thus a movement of the ribs backwards and forwards alternately is facilitated, and such movements, we shall hereafter see, are continually repeated in the process of breathing ^S- THE SKELETON OF THE HEAD. § 22, The remaining part of the axial skeleton is that familiarly Fig. 2S.— The Skuij-, viewed Dorsally. /. Frontal. J. JIalar. I. Lnclirj-nial I*. Ijai'liryiiuil foramen. la. L.'inilKlnidul riil|.;e. m. Maxillary. 71. Nasal. p. I'alatinp. pf. Post-orbital process of frontal. J)/. P()st-nrl)ital jirocess of malar. pm. Premaxilla. *. Sajiittal suture. X. Posterior \, bplicno-iialatinc foramen. known as the skull. This bony structure affords shelter to the brain, and is also the seat of certain organs of special sensation — CHAP. III.] SKELETON OF THE HEAD AND TRUNK. 57 namely, those of lieaiing, sight, and smell. It may he descrihed as an irregularly and comi)lcxly shaped osseous hex with an arch, like a flyiug buttress, on each side, all forming one coherent mass, and Avith very diversely conditioned arches appended below and not similarly coherent. The first of these inferior arches is the skeleton of the lower jaw, or niaiK/ible. The second is the bony framework to which tlic tongue is attached, the ////oid Both these inferior arches readily fall away from the rest of the skull when the soft parts are dissolved or otherwise removed. Apart from these arches (both inferior and lateral) the skull consists of a spheroidal posterior portion (p), to which is annexed iu front an elongated, narrower, and irregularly quadrilateral part, made up of the bones of the face. On each side of the skull (just in front of the spheroidal portion) is a large smooth concave surface (with the concavity outwards), which forms the inner wall of the chamber for the eye, or the orhif ; and the skull is especially narrow from side to side at the hinder and lower part of this region. The greater part of the upper region of the skull is smooth and even, and crossed by undulating lines of bony union called siitares{s). When a section is made lengthways (Fig. 49) through the skull, its spheroidal portion is shown to bound a great posterior cavity (for the brain), in front of which is a more solid region — the quadrangu- lar part — which includes the bones of the nose (Figs. 49 and 50, uio, ct), and is placed above the mouth and between the eyes. The skull consists of two parts : — (1). The brain-case, skull proper, or cranium. (2). The skeleton of the face. Certain conspicuous openings and prominences are found in different regions. The projecting portion of the back of the head is termed the occiput, and at its inferior hinder part is a large hole, looking down- wards and backwards, termed the occipital foramen, or foramen magnum (Figs. 29 and 47, _/)«). On each side of this hole, forming part of its margin, is a rounded projection ; and these projections (Figs. 29 and 47, oc), termed " occipital condyles," articulate with the cup-shaped articular concavities on the anterior side of the atlas vertebra (Fig. 21, B, ;:). Thus, all but the front part of this foramen (to which the odontoid process is attached by ligament) coincides with the corresponding portion of the ring of the atlas vertebra, and the interior of the skull forms the expanded anterior end of the vertebral neural canal. If the skull be turned base upwards (Fig. 29) a large globular prominence {h) will be seen a little in front of and external to each occipital condyle. Each such prominence is called, from its connec- tion with the internal ear, an auditory hulla. Between the bulla?, the under surface of the cranium extends forward as a narrow flat surface (Fig. 29, ho and pii), bounded laterally by two low, elongated bony plates {pt), external to which is, on either side, the wide cavity of the orbit enclosed by the bony arch just referred to, which arch is 58 THE CAT. [chap. III. termed the zj/fjoma (Z). At the hinder end of the zygoma is a trans- versely extended, smooth concavity called the (jknoid surface {g). The under surface of the face (formed by the bones of the roof of Pig. 20.— Under Surface of Skull The two openings onclosecl liy tlic ]ire-inaxillic and maxilla: are the anterior palatine foramina. t. Amlitorj' bulla. ho. ]5!iKi-occi]iitiil. hs. Basi-splienoiil. c. Canino. fm. Koranicn nKiKiinin. (/. Olcnnul surliai-. i. Incisors. j. Malar. 7/1. Maxillii. 1(10. Millar. Ills. Mastoid procps.s. fw. Oi'(i)iital coiidyk'. J3J). l'alaliii(!(iilaciMl one aliovc, tlic (itlicr lic- ueath the ojieuiiig ol the iiostorior nari's). })/. Post-orliital jirocrss of frontal. ///'. l'ost-orl)ital jirocess of malar. ■pin. Prc'-maxilla. jmio. Pro-molars. pp. Par-occi]iital process. ps. Pre-siilionoid. pt. Pterygoid prooess. fo. Su]ira-occipital. /. Posterior root of zygoma. :i. Palatine foramen. s. Siilienoidal lissure and foramen mtundns !'. l'oian\en ovale. 111. Ku.staeliian opening. 11. Foramen laecioini jiosterins. the mouth) lies at a .slightly different level from that of the base of the cranium. The two low, elongated bony plates {pt) just spoken of connect these two surfaces together on each side, but in the middle line, leave a vacuity between them, which is the hinder opening of the nostrils, or jwsfcrior iKircs (.shown, in Fig. 29, by the CHAP. III.] SKELETON OF THE HEAD AND TRUNK. 59 shadow in front of ^s), which bounds the base of the cranium in front as the foramen magnum bounds it behind. The middle of the hinder part of the under surface of the face thus forms the ventral margin of the hinder nostril, while on either side, the face receives the termination of the arch of the z5^goma. It thence narrows as it proceeds forwards, forming a triangular bony plate, slightly truncated in front, and bordered by teeth. When the skull is looked at in front, we see on each side of its highest part, with its rounded outline (the forehead), the great Fig. 30.— Skull viewed from in feont, with the Lower Jaw detached. an. Angle of mandible, c. Canines. c. (Of lower jaw) ooronoid process. / Frontal. i. Incisors, m. Maxilla. n. Nasal. ■pf. Post-orbital process of frontal. jij. Post-orViital process of malar. -pm. Pre-maxilla. ■pmo. Pre-niolars and inferior true molar. y. Condyle of niandil)le. 2. Infra-orbital foramen. 13. Mental foramen. sockets for the eyes, termed the orhits. These are not completely surrounded by bone, but are bounded below and externally by the zygoma and a process (j/?/), and above by another process {pf) from the skull roof, and behind by the wall of the cranium. The part of the skull which juts out laterally to support the floor of the orbit is called the " malar prominence." Between the orbits is the bony pro- minence of the nose, beneath which is a small, somewhat heart- shaped aperture, the front bony nostrils or anterior narcs. Beneath each orbit is the small bony cheek, and the skull is bounded below (the lower jaw or mandible being removed) by the alveolar border giving attachment to the teeth. 60 THE CAT. [crap. hi. "When the skull is viewed in profile its upper margin is seen to present an even, rounded contour. Its lower margin is nearly straight, with irregular prominences. The line of the occiput (Fig. 46, c to .y) inclines somewhat hackwards as it ascends. In front, the skull is bounded by the margin of the antei'Ior nares. The zygoma arches upwards, backwards, and then downwards to the front of the auditory bulla, eucloshig, as well as the orbit, a fossa named "temporal," because a muscle called the "temporal muscle" is there placed. Behind and beneath the hinder end of the zygoma is a noticeable aperture, which is the external bony opening of the ear (ac). A ridge also runs upwards from the malar pro- minence, and forms the anterior margin of the bony orbit. The orbit is bounded behind by an ascending and a descending post- orbital process, which nearly meet. The skull is said to be divided into certain regions. Thus we have the base or hasi/ar region, and opposite to it the vertex, or sincipilal region ; ^xc have the region of the forehead, or frontal region, and opposite to it that of the back of the head, or occipital region. At the side of the head we have, posteriorly and above, the parietal^' region {p) ; beneath this, and ^^■ithin the arch of the zygoma, the temporal region. The skull is made up of different bones of very different sizes, shapes, and degrees of density, which are variously united together by sutures. When the skull is looked at from above, a transverse zigzag line of union is seen to run across behind the forehead ; this is called the coronal suture. Its zigzag appearance is due to the interlocking of little processes which project from the adjacent margins of the bones, the presence of Avhich causes the suture (or line of iniion) to be what is called " dentated." Running directly backwards and forwards from this, along the middle line of the skull, is another suture — at right angles to the former — termed sagittal (Fig. 28, .s). The sagittal suture ends posteriorly by joining a wide V-shaped suture with the apex upwards, which is called latnhdoidal. Turning now to the lower jaw ; this when attached to the skull is seen to fit, by a cylindrical-shaped head, or " coiuli/lr," into a depression placed on each side in front of the external auditory opening, the (jlcnoid .surface before mentioned. The number of bones forming the skull decreases Avith age, by anchylosis. In its mature condition the skull of the cat consists of the following twenty-seven bones : the occipital, two parletals, two frontals, two temporals, the sphenoid, the presi)henoId, the ethmoid — which ten bones compose the cranium, or skull proper ; two maxillaries, two premaxlllarles, two nasals,' two malars, two lachry- mals, two palatines, two turbinals, one vomer, one mandible (In two ♦ Because it is here the "i)anetul bono " is situate. CHAP. III.] SKELETON OF THE HEAD AND TRUNK. 61 parts), and the liyoid bone* — seventeen bones in all, form the skeleton of the face. § 23. The OCCIPITAL rone is of course that of the occiput, and it surrounds the great occipital foramen, or foramen magnKm {fin). AVhen detached, it is seen to be somewhat lozenge-shaped, but rounded above and truncated below. It is made up of a crescentic plate of bone extending above and beside the foramen magnum, and of another narrower and quadrangular plate of bone, which, joining A. External surface. B. Internal surface. io. Basi-occipitiil. c. Ci)ndyle. t?). Cerebellar fossa. Fis- 31.— The Occipital. B CO. Ex-occipital. fm. Foramen niagnnm. /. Laniljiloiclal riilge. j>. Par-occipital proces.s. so. Supra-occipital. the other, bounds the foramen magnum below, and thence extends forwards. The part above the great foramen (so) is the supm-occipital bone, while the parts placed one on each side of it (eo) arc the cx-occipitah, the quadrangular plate in front {ho) is^ the hasi-occipitnl, and these four are all separate and distinct bones in the young kitten. The margin of the supra-occipital projects outwards as a bony ridge (/), wdiich descends on each side of the occiput, and is called the lamhdoidal ridge or occipital ridge, and affords a special surface for muscular attachment. The outer surface of the supra- occipital is undulating and more or less convex. Its inner surface presents shallow depressions or fossae, one of which {cb) is placed medianly above the foramen magnum, and lodges the middle portion of that part of the brain called the cerebellum. The hasi-occip>ital narrows somewhat as it advances forwards. Its upper surface exhibits a smooth concavity, the basilar groove, which supports that part of the nervous centres termed the " medulla oblongata " Each part of the bone which bounds the foramen magnum on each side, i.e., each ex-occipital, supports one of the condyles before * Really made up of .several distinct bones ; but lieie, for the sake of simplicity and clearnes.s, spukeu of a.s oue. 62 THE CAT. [chap. hi. noticed. The condyles (c) are elongated convex prominences placed somewhat obliquely, converging forwards. The inner border of each is rough, for the attachment of one of the " check " ligaments. In front of each condyle is a perforation, the anterior condyloid foramen (1), which allows the hypoglossal nerve to pass out from the brain, while a canal (the hinder opening of which is a little within the margin of the foramen magnum) traverses the ex- occipital on its inner aspect. External to each condyle is an expanded process of bone called the par-occipital 2))'occsf^ (j)), the front surface of which is applied to the posterior surface of the auditory bulla. The root of the par-occipital process forms the hinder boundary of the aperture of the skull through which the jugular vein comes out, which aperture is called the foramen lacerum jugulare, or foramen lacerum posterius. A small triangular bone, the interparietal, in the fully mature cat blends completely with the supra-occipital, but long remains a distinct ossicle. Its base is applied to the mid -part of the superior border of the occipital, while its sharp apex extends forwards between the parictals. It is strongly con- cave within (especially in the transverse direction), but is convex externally. If this be counted as a part of the occipital, that bone may be said to articulate above by its superior margin with the parietals, and below this, on each side, with the hinder margin of one of the temporal bones, while each par-occipital process (as before said) applies itself to the hinder end of one of the ordinary bulhi?. The basi- occipital adjoins the hinder part of the bone next in front, namely the sphenoid. § 24. The PARIETAL bone forms, with its fellow of the opposite side, the main part of the roof of the cranium. It would be quadrangular in figure but that its upper, hinder angle is rounded off, and it is strongly convex outwards, and concave within. Its greatest convexity is termed the parietal eminence {e). Above tliis is a curved ridge convex upwards, marking the superior limit of the temporal fossa. Within, the parietal is marked by grooves for blood-vpssels, and its upper margin is traversed by a longitudinal depression, which forms, with the help of the opposite parietal, a longitudinal wide and shallow groove for a blood receptacle called the longitudinal sinus. The two parictals are connected together above by the sagittal suture ; each is connected by the lanibdoidal suture with the interparietal, and with the supra-occipital. The parietal also articulates anteriorly (/) Avith the frontal by the Fig. 32. — Inter- parietal Bone. A. Outer surface. B. Inner .surface. a. Apex which liasses forwards between tlie pa- rietal bones. h. Hinder margin. c. Fossa for recep- tion of part of brain. * It has not therefore been reckoned as a distinct bone in the list before given of the bones of the cranium and face. CHAP. III.] SKELETON OF THE BEAD AND TRUNK. 63 coronal suture, and below with the temporal bono by a suture (sq) which is called sqnaiiions, because the margins of the bone it joins are so bevillcd off that the temporal lies on the parietal like a scale. From the hinder margin of the parietal a plate of bone extends for- wards at an acute angle, with a strongly concave free margin. This plate divides one part of the brain from another, and is an ossifica- A B Fig. 33.— Right Parietal Boxe. A. Internal surface. B. External surface. c. Paiietal eminence. /. Surface for articulation with frontal. s([. Surface for temporal bone. t. Tentorium. tion of a membrane called the tentorium, and described with the brain structures (f). The parietal is always a single bone. § 35. The remaining bones of the roof of the skull are the FK.ONTALS, whicli He side by side in front of the parietals, and roof over the hinder part of the face as well as the front part of the The suture which divides them is termed the "frontal cranium. Fi''. 34.— The Frontal. A. E.Kterual aspect. B. Internal aspect. /. Surface .joiuinj; the other frontal. /((. Outer wall of na.sal fossa. m. Nasal process. op. Orliital jiart of laieral jilate. tp. Tciiipor.-il part of lateral plate, J). I'rc-orbit.'il process. ^lo. I'ost-orbital iiroces:-. suture," and is the direct continuation forwards of the sagittal suture. The frontals together form a considerable, rather convex triangular expansion above, the outermost part of which is the post-orbital process (j^o) of the hinder part of the orbit ; while behind this the frontal forms part of the temporal fossa. But the greater part of each frontal is its lateral part (op), which descends from the outer margin, almost at right angles with its 64 THE CAT. [chap. m. upper surface, as an undulating plate (concave externally in front, and convex beliind) with a cre.scentic inferior margin. The hinder, externally convex, part of this plate forms part of the temporal fossa; the anterior, externally concave, part of it forms the inner wall of the orbit, and (towards its front end) the outer wall of the nasal cavity. Viewed internally, each frontal shows above, a flattened surface (/) for junction with its fellow of the opposite side ; behind this is a deep concavity for part of the brain, and in front, a flattened and irregularly roughened surface {/'() — the outer wall of the hinder part of the nasal cavity. Thus, the two frontals together have, when viewed from below, somewhat the figure of a bisected hour-glass. There is, behind, a large conical cavity (with the apex forwards) for the brain, while in front is a smaller conical cavity (with the apex backwards) — the nasal chamber. Consequently, when the two frontals are seen together from behind, they exhibit a deep median notch, open below, indi- cating the point of communication between the anterior and posterior conical cavities just mentioned, and situated at the point where each frontal is laterally constricted. This notch, in the perfect skull, is filled up by a bone called the ethmoid, which forms the hinder end of the nasal chamber. At its anterior end, each frontal bifurcates laterally into a sharp pointed "nasal process" (m) and a more obtuse " pre-orbital process " (p). Between these processes each frontal receives an ascending process of the maxillary bone. A'^'liile the two nasal bones are received between the slightly diverging nasal processes of the two frontal bones (see Fig. 28). Within the substance of the middle upper part of the bone is a ca^dty, more or less tilled with air, called the frontal sinus, which cavity is prolonged out into the post-orbital process. The frontals articulate behind, with the parietals ; laterally, with the orbito- and ali-sphenoids, and sometimes also with the temporals; below with the palatines, the maxillaries, the ethmoid, and the lachry- mals ; in front, with the maxillaries and nasals. § 26. On each side of the hinder part and base of the cranium wo find an exceedingly complex bone, called the temporal. "When looked at externally it exhibits a very conspicuous oval opening (the meatus auditofius extcrnas), which is the aperture (inc) leading from without t9 the internal car. From in front of this a bar of bone, the zygomatic 2)roccss {%), arches horizontally forwards and outwards, and contributes, with the large plate of bone above it {sq), the squamous clement of the temporal bone, or the " sqiiainosal." This bony plate is convex without and concave within, and with a very rounded superior margin, which overlaps the lower part of the out- side of the parietal bone above. The zygomatic process is somewdiat arched vertically, and is bevelled off at its distal end, which lies upon the niahir bone. At its hinder end this process has beneath an ehmgated surface, concave from before backwards, and termed the glenoid surface {g). CHAP. III.] SKELETON OF THE HEAD AND TRUNK. 65 In its natural state it is coated with cartilage, and serves for the articulation of the lower jaw. This surface is limited behind by a sharply descending bony plate — the post-glenokl j^^'ocess (gj)). A ridge of bone is continued backwards from the hinder end of the zygomatic process, over the external auditory meatus, and is called the posterior roof of the zygoma, the part supporting the glenoid surface, forming the anterior root of the zygoma. The bone which bounds inferiorly the external auditory opening is that which forms the auditory bulla already spoken of. This is rounded, and smooth on the surface, and rather longer from before backwards than transversely. It is at first made of two parts : an external part, consisting of a crescentic plate of bone, broader in front than behind — the tympanic (so called on account of its Fig. 35.— Temporal Bone. A. External view. B. Internal view. h. Inner and larger part of bulla. c6. Cerebellar fossa. eu. Eustachian opening. g. Glenoid surface. ijp. Post-glenoid process. w. Mastoid region. me. Meatus auditorius extemus. mi. Meatus auditorius internus. ms. Mastoid i)roces.'!. J). Surface applied to jiarietal. sq. Squamosal. t. Outer and smaller part of bulla. X. Aqueductus cochleai. z. Zygomatic process. 12. Stylo-niastoid foramen. A ijroeess of the malleus is seen in Fig. A, ex- tending downwards and forwards within the auditoiy meatus. connexion with the drum of the ear) — and an internal, much wider part — the ento-tympanic — which forms all the rest of the bulla, which is naturally visible on the base of the skull. Between the anterior end of the tympanic and the post-glenoid process is a narrow chink, termed thejissura Glaseri, which transmits the chorda tympani nerve. At the hinder end of the tympanic, beneath the posterior end of the posterior root of the zygoma, is an opening (12), called the stylo- mastoid foramen, which gives exit to the facial nerve. Immediately below and within this foramen there is a small pit in the tympanic, at the bottom of which a minute cylindrical ossicle, called the tympano-hyal, may be detected, which serves to give attachment to the uppermost and cartilaginous portion of the anterior, or lesser cornu of the hyoid (Fig. 46, t*). The only remaining part of the temporal bone visible externally is a very small and narrow triangular tract, which extends upwards 66 TEE CAT. [CHAP. iii. and backwards (its apex "being above) from above tbe stylo-mastoid foramen and bebind tbe posterior root of tbe zygoma. It is rougb externally, and forms tbe lower part of tbe lambdoidal ridge, the upper part of wbicb is formed hj tbe occipital bone. Opposite tbe posterior root of tbe zygoma it adjoins tbe par-occipital process, and below that point of junction it narrows into a nipple-shaped process applied externally to tbe tympanic, and descending, immediately bebind tbe stylo-mastoid foramen, to the pit for the tyrapano-hyal. This triangular tract is the mastoidal region {m) of the temporal bone, and tbe process just described is the mastoid process (ms). On its inner aspect, below and bebind tbe squamous part (sq), tbe temporal bone exhibits a triangular irregularly-shaped mass of very dense osseous tissue. This is the ^jetroiis part of the temporal bone, or tbe "petrosal." The petrous and mastoidal portions of the bone enclose tbe inner and essential parts of the ear, the internal canal leading to which — the meatus auditoriiis intcrnus — is the con- spicuous opening seen on the inner surface of tbe petrosal {mi). This opening is di\ided within by a horizontal bony lamella into two parts. The openings for the auditory nerve filaments are below this horizontal lamella, while tbe opening above it gives entrance to the facial nerve, which thence proceeds to tbe st5do-mastoid foramen, traversing in its way a canal termed tbe Aqueduct of Fallopius. Above the opening of the internal auditory meatus there is, on the inner wall of the petrosal, a depression or pit (e^), (which lodges a process of tbe cerebellar part of tbe brain) surmounted by a prominence which indicates the place of the anterior vertical semi-circular canal of the internal ear. Below and in front of this prominence is a small foramen, tbe hiatus Fallopii, which transmits the superficial petrosal nerve, and leads back into the Aqueduct of Fallopius already mentioned. Just bebind tbe shallow depression above mentioned, and close to the posterior margin of the petrosal, is a small vertically elongated opening, called the aquceductus rcstibuli. A still smaller aperture j)laced close to and directly bebind the internal auditory opening (a-), is the aqucductus cochlcce. Both these openings transmit small veins of tbe internal ear. Between tbe anterior part of the petrosal bulla and the ali- sphcnoid is a largish opening {eu^, wbich is that of the EustacJiian tube — a channel serAing to convey air from the mouth to tbe ear. Tbe inner part of tbe canal is incompletely partitioned off by a small bony lamella — (tbe processus coclileariformis). This rather con- siderable Eustachian aperture is naturally roofed over and covered by a backward expansion of the alispbenoid. On the inner side of it, at the binder portion of the junction of the squamosal and petrosal portions of the temporal bone, on its inner surface, is a groove wbicb receives a venous canal, namely one of tbe two branches into which the median venous channel (before noticed as passing along beneath the median junction of the parictals) divides as it descends. This groove may lead into a canal opening CHAP. III.] SKELETOX OF, THE HEAD AXD TRUNK. 07 by a foramen just bcliind the post-gleiioid process — a post-gJenoid foramen. Tliis, however, is generally absent. The margin of the petrosal, above the cerebellar fossa and internal meatus, developes a bony ridge, which unites with the tentorial plate, before described as passing downwards and forwards from within the parietal. The cavity of the bulla is almost completely di\aded within into two very unequal parts by a bony septum which ascends from the Fig. 3G. — Vlktical Section of the Alditorv Bulla of the Tiger (Fhaxr).