CHAPTER XIX 



CARNIVORES concluded 



EARED SEALS, WALRUSES, AND SEALS 

 Families OTARIID^E, TRICHECHID^;, and 



THE whole of the Carnivores treated of in the preceding chapters constitute 

 the more typical representatives of the order, and are hence collectively termed by 

 zoologists true or fissiped Carnivores. In contrast to these is a much smaller group 

 comprising the eared seals, the walruses, and the true seals, differing from the 

 above by their flipper-like limbs, and hence known as the pinniped or fin-footed 

 Carnivores. By some writers the pinnipeds are regarded as entitled to form an 

 order by themselves, quite distinct from the Carnivores; but by the majority of 

 naturalists, in England at least, they are considered to form merely a suborder. 



The members of the pinniped group have their entire organization adapted for 

 an aquatic life; this adaptation showing itself most markedly in the structure of 

 their limbs. Thus both the fore and hind-limbs are modified into paddle or flipper- 

 like organs, with nearly the whole of their upper portions, as far as the wrist and 

 ankle, inclosed in the common integument of the body; while the feet themselves 

 are greatly elongated more especially in the hind-limb and much expanded, 

 with the whole of the five toes completely connected together by web. A peculiar- 

 ity of the toes of the hind-foot is to be found in the circumstance that the first and 

 fifth toes, that is to say, those corresponding respectively with the human great and 

 little toes, are stouter, and in most cases also longer, than the three middle toes; an 

 arrangement which is quite unknown among the true Carnivores, where the first toe 

 is the shortest of the series. The pinnipeds are also characterized by the structure 

 of their teeth, which are simpler than those of the true Carnivores, and never show 

 a specially-modified "flesh-tooth" in one jaw biting against a somewhat similarly- 

 modified tooth in the opposite jaw. As a general rule, the cheek-teeth comprise 

 four premolars and one molar on either side of each jaw; all these teeth being very 

 similar to one another in general structure, and usually consisting of a pointed main 

 cone, which may be flanked in front and behind by smaller cones so as to produce 

 a tricuspid tooth. Moreover, the number of incisor teeth is invariably reduced 

 below the typical three pairs in each jaw; there being very frequently three pairs of 

 these teeth in the upper, and two in the lower jaw, or but two pairs in each jaw. 

 Then, again, all the pinnipeds are characterized by the reduced or rudimentary 

 condition of their milk or baby series of teeth; these teeth being never of any real 

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