Page:The American Cyclopædia (1879) Volume IV.djvu/19

CARNIVORA 11 belli is bony, evidently to protect the brain during the sudden movements of leaping upon their prey, and the whole bony structure is re- markably solid; the lower jaw is strong and short in proportion to the carnivorous propen- sity of the genus. The vertebrae of the neck are remarkable for the size of the first two ; the dorsals and the number of ribs vary from 13 (the jnost common) to 16 ; the lumbar verte- brae, always numerous in proportion to the leaping powers, vary from 4 to 7 ; the sacrum is composed of several vertebrae, and in the bears is remarkably broad, for the support of the body in their frequently erect position ; the tail is the longest in the most active species, as in the lion and the panther. The shoulder blade is flat and broad ; the clavicle, when not entirely wanting, is quite rudimentary ; the humerus is arched, short, and strong ; the bones of the forearm have but little motion on each other, except in the ursidce, and the ulna is generally placed behind the radius, both of them in the seals being broad and flat ; the me- tacarpus is much larger in the digitigrades than in the plantigrades. The retractile claws of the felidce are described in the article OAT, in which family they are most developed. The pelvis is short, and its bones broad and flat ; the thigh bone is moderately long, and directed immedi- ately downward, except in the seals, in which its direction is outward. The bones of the leg are generally separate ; the tarsus consists of the usual five bones, but the tuberosity of the os calcis is quite long and strong ; the inner meta- tarsal bone in the cats and dogs is merely rudi- mentary ; in the weasels the inner toe is small, in the cats wanting, and in the plantigrades in the same range as the others ; in the planti- grade foot everything is arranged for slow and steady walking, in the digitigrade for leaping and tearing, and in the pinnigrade for swim- ming. The muscles in this order, especially of the jaws, neck, and anterior extremities, are enormously large and powerful. In the typical carnivora, the incisor teeth are small, and placed in the intermaxillary bone ; the canines, situa- ted above, at the junction of the intermaxilla- ries with the superior maxillaries, are strong, long, and cutting, slightly curved, and admira- bly adapted for tearing their prey ; the cheek teeth have cutting edges, the lower shutting within the upper like the blades of scissors, and are provided with sharp triangular processes ; the teeth are arranged in a short space, and their action is rendered more efficacious by the shortness of the whole jaw, and by the simple hinge-like motion of the lower jaw ; in the seals the canines are much smaller, but the cheek teeth are furnished with numerous sharp points for the purpose of holding the slippery and scaly fish upon which they feed ; in the bears the jaws are much longer, and the molars are flattened and tubercular, indicating the far less carnivorous propensities of this family. The carnivora, in proportion to their approach to the typical felidce, whose food when swallowed is so like their own tissues that it is ready for speedy assimilation, have a short intestinal ca- nal ; in the lion it is but three times the length of the body, and has very few internal folds, and a very small caecum, while in man it is five times as long, in the horse 10 times, in the sheep 28 times ; such is the relation between the organs, that the form of the teeth indicates the charac- ter of the intestinal canal, the armature of the feet, the mode of progression, and very nearly the habits and mode of life of an animal. The lobes of the liver vary in number from four in the badger to eight in the lynx, without any apparent physiological reason; the hepatic ducts correspond in number to the lobes, and the common duct, before it enters the intesti- nal cavity, frequently receives a pancreatic duct ; the gall bladder is always present, and in the ursidce is of great size ; the pancreas and spleen do not differ, except in form, from these organs in other mammals ; the chyle is so noted for its opacity and whiteness, that the discov- ery of the lacteals was made in these animals long before they were seen in man. The car- nivora belong to the sub-class gyrencephala of Owen, in which the cerebral hemispheres are the largest developed (except in man), extend- ing over a portion of the cerebellum and the olfactory lobes ; in this arrangement they are next to the quadrumana or monkeys ; the hemi- spheres have well marked though simple con- volutions. The organs of sense are well devel- oped ; in the diurnal carnivora the pupil is round ; in the cats it is elongated vertically, and in a very bright light almost linear, but it is round in the dark, causing the brilliant tape- turn of the posterior arch of the choroid to ap- pear like a ball of fire ; the large size of the mastoid process, communicating with the cav- ity of the tympanum, indicates considerable acuteness of the sense of hearing, necessary for animals seeking their prey during the stillness of night ; the sense of smell, especially in the ccmidce, is very acute, and the pituitary mem- brane is extended greatly by means of the com- plicated convolutions of the turbinated bones ; the sense of taste is probably not very acute, and the tongue of the cats is covered in its mid- dle portion with horny spines, well calculated to tear the flesh from bones. The kidneys in some families, as in the bears and seals, are much subdivided, resembling a bunch of grapes; in the cats the divisions are hardly perceptible. In the civets and allied genera there are glan- dular follicles, which secrete a peculiar odorous substance, sometimes exceedingly fetid ; the glands are usually situated near the anus, and the excretory ducts open between the rectum and the genital organs. The testes are gener- ally pendulous and external, but in the seals they remain permanently within the abdominal cavity; the vesicuke seminales do not exist, but organs resembling the prostate and Cow- per's glands are generally found ; in almost all there is a bone in the penis, the hyaena forming an exception, it is said ; the teats are abdomi-