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 3/3, 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.[1] This genus also has the more 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.
Fig. 228.—Patagonian Sea-Lion. Otaria jubata. × 1⁄20.
There is no doubt about their close resemblance to the
- ↑ Murie, Trans. Zool. Soc. viii. 1874, p. 501.
