58 



toes. Fur rather rough, of the head, neck, and chin longer ; hair 

 cylindiical ; under-fur none. 



FijT. 18. 





fk.^^ 



Otaria leouina. Skull. 



The skulls of the adult Arctocephali have been mistaken for the 

 skulls of this genus, but the form of the hinder part of the palate, 

 which is little altered by the age of the specimens, at once separates 

 the two genera. I was formerly inclined to believe that the form of 

 the hinder part of the palate altered ; but the examination of the 

 skin, with its skull attached, of an adult ArctocepJialus lohatus has 

 proved that it does not alter. 



N Otaria, sp., Teron Sf Lesueur, Voy. Terr. Austr. ; Desm. Mamtn. ; Nilsson, 



. i g -( Vet. Akad. Hundl. 1837 ; Skand. Fauna, t. ; Wiegm. Arch. vii. 



I * Platyi'hynchus (Platyrliinque), F. Cuvier, Mem. Mus. ix. 209. t. 15. 



f. 2 ; Diet. Sci. Nat. lix. 465 ; Oray, in Brookes' s Cat. Mainm. 37, 



1828 ; Fischer, Si/n. Mamm. 231. 



Otaria, Gray,Zool. Erebm Sf Terror ; P. Z. S. 1859, 360 ; Turner, P. Z. S. 



1848, 88. 

 Platyi'hmus, Lesson, Manmi. 204. 



There is doubtless a great difference in the development of the 

 skull in the male and female Seals, but unfortunately the sex of the 

 specimens from which the skulls have been derived is often not 

 marked. In the only species where I have been able to observe this 

 fact, almost the only difference was in the size and in the strength of 

 the markings on the skull, and in the size of the canine teeth. The 

 full number of the teeth of these animals is developed early in life ; 

 and the canines of the second set are gradually developed, the roots 

 being far in the socket, and jjrotruded as the jaw enlarges. 



The changes in the form of the palate and in the distance between 

 the teeth of the same set in the younger and older skulls of the same 

 species after they have obtained their fuR set of teeth are very great 

 — quite as much as the difference in the external form of the skull 

 produced by the development of the occipital ridges, &c. — P. Z. S. 

 1859, 360. 



