474 



CARNIVORA. 



tain species, In Ph. vitulina for instance, and ap- 

 pears to harmonize with the tendency to scanty 

 deposition of bony matter, which characterizes 

 the whole cranium in this family. The con- 

 dyles in these animals are also very much 

 larger than in the other carnivora. 



The sphenoid bone has nothing very remark- 

 able in its structure, excepting the greater 

 developement of its alae in these than in most 

 others of the mammalia, and the small com- 

 pressed triangular form of the pterygoid pro- 

 cesses which in the cats are long and hooked 

 backwards. 



The superior maxillary bone consists of the 

 true or posterior maxillary ( c) and the intermax- 

 illary (a) portions. For the sake of clearness 

 they may be described as distinct bones. The 

 body of the maxillary bone extends very high up 

 in the cats, and is remarkably strong and compact. 

 In the seals it is encroached upon by the nasal 

 opening, so as to leave only a narrow neck be- 

 tween that opening and the orbit. The infra- 

 orbitar foramen is remarkably large in the cats 

 and in the seals, in which animals the long elastic 

 setaceous whiskers are so useful as feelers, and 

 are supplied with large filaments of the infra-or- 

 bitary branch of the fifth pair of nerves. The 

 length of the body of this bone depends on 

 the number and nature of the teeth which are 

 imbedded in it, and is shorter in proportion to 

 the predominance of the strictly carnivorous 

 appetite. The canine teeth and the molares 

 are those which occupy this bone, the incisores 

 being placed in the intermaxillary; and in the 

 cats the body of the bone is remarkably short, 

 being occupied only by four molar teeth, the 

 first of which is small and rudimentary, as 

 well as the posterior one, which is small and 

 tubercular ; the two middle ones are formed for 

 cutting asunder the flesh, and are exceedingly 

 strong. In the bears the teeth assume more of a 

 tubercular form,and are, infact, adapted for mas- 

 ticating vegetable substances as well as animal 

 matters; the jaw-bone is, therefore, much longer 

 than in the cats. In the dogs, which hold an 

 intermediate place in this respect, the molar 

 teeth are six in number, and the two posterior 

 ones are more or less tubercular. The anterior 

 part of the jaw is enlarged and rounded for 

 the location of the large and powerful canine 

 teeth. In the Walrus (Jig, 195,J the anterior 

 part of this bone is greatly enlarged for the 

 enormous canine teeth, which form powerful 

 weapons, with which the animal strikes directly 

 down with immense force. 



The intermaxillary bones contain each three 

 small incisor teeth : these in the cats are 

 very small, excepting the external one, which 

 is somewhat larger than the others. In the 

 seals they are pointed. These bones are con- 

 siderably smaller in the carnivora than in most 

 other orders. 



The nasal bones (b) are smaller in this order 

 than in many others. In the cats they are 

 rather broad anteriorly, but short; they are 

 longer in the dogs and bears, agreeably to the 

 greater length of the face generally. In the 

 seals they are much shortened, in order to allow 

 of the great expansion, in an upward direction, 



Fig. 195. 



of the nasal aperture, by 

 which, when in the water, 

 they more readily raise 

 their nostrils to the atmo- 

 sphere for the purpose of 

 breathing. 



The malar bone (h) per- 

 forms a very important 

 office in the carnivorous 

 group, as the zygoma re- 

 quires to be very exten- 

 sively developed for the 

 protection of the enormous masses of mus- 

 cle which are needed in tearing the food of 

 these animals, as well as for the attachment of 

 the masseter. The zygomatic arch in this order 

 is convex upwards as well as curved outwards, 

 by which form a great increase of strength is 

 acquired in the direction of the muscular 

 force. 



The lacrymal bone is said to be wanting in 

 the seals. I believe I have seen a trace of its 

 existence in a rather young cranium of Phoca 

 vitulina. The remarkable vacancy which oc- 

 curs in some of this tribe in the orbito-temporal 

 fossa, between the frontal, the maxillary, and 

 the sphenoid bones, has been supposed by 

 Meckel to indicate the place which the lacry- 

 mal bone should occupy; but as this hiatus 

 does not exist in several species, in which the 

 absence of this bone is equally evident, this 

 supposition is probably not correct. 



The inferior maxillary bone (i) follows of 

 course the general structure of the superior. 

 It is remarkably short in the typical forms of 

 the carnivora, and more elongated in the others, 

 particularly in the bears. Indeed this bone, 

 like the upper jaw, is shortened exactly in pro- 

 portion to the carnivorous propensity of the 

 animal. The ascending plate is also remarkably 

 developed, and offers a surface of great extent 

 for the insertion of the elevators of the lower 

 jaw. 



The character of the vertebral column in 

 the Carnivora offers some interesting varieties 

 of form, depending principally on the degree 

 of exertion, of activity, or of flexibility re- 

 quired by the habits of the different genera. 

 The strength and size of the two first cervical 

 vertebrse, the atlas and dentata or axis, have 

 already been alluded to. The first is exceed- 

 ingly broad and robust, with strong transverse 

 processes; the second is long, with an enormous 

 spinous process. The remainder of the cervi- 

 cal vertebra are generally rather elongated in 

 most of the genera, but in the seals they are short 

 and but little developed. In general, also, the 

 spinous processes are considerable, and either 



