448 TEETH OF SEALS CHAP. 
six, and the additional molar was at the end of the series, thus 
suggesting a lengthening of jaw coupled with an increase in 
number of teeth. 
The incisor teeth of the Pinnipedia differ from those of the 
land Carnivora in that there are nearly always fewer than 3, at 
least in the adult animal. In possessing lobulated kidneys the 
Pinnipedia differ from all terrestrial Carnivores except the Otters 
and Bears—a significant fact. 
In the characters of the skeleton the Pinnipedia show many 
peculiarities. The cranial part of the skull is proportionately 
to the facial part greater than in terrestrial Carnivora; there is 
no lachrymal bone, and the orbit is to some extent defective in 
ossification. The alisphenoid canal, so important a feature in 
the Carnivora, may be present or absent. It is present, for 
example, in Otaria jubata.' This genus also has the more 
ay, 
1 
Fic. 228.—Patagonian Sea-Lion. Ofaria jubata. Xx 
primitive small and rugged tympanic bullae, which are inflated 
and more Cat-like in others. The vertebrae show an interesting 
Creodont peculiarity in the complex interlocking arrangements of 
the zygapophyses of the dorsal vertebrae. The ossicula auditus 
differ from those of their terrestrial allies in their large size and 
massive growth. In this they have come to be like those of the 
Whales and Sirenians. 
There is no doubt about their close resemblance to the 
1 Murie, 7rans. Zool. Soc. viii. 1874, p. 501. 
