284 ZALOPHUS CALIFORNIANUS CALIFORNIAN SEA LION. 



palato-masillary suture is about opposite the hinder edge of 

 the last molar. The pterygoid hamuli are small. The posterior 

 uarial oi^eniug is wider than deep; the anterior has these two 

 dimensions about equal. 



In Zaloj)hus the superior aspect of the skull, before the devel- 

 oi^ment of the crest, is strikingly like that of Arcfocephalus, as 

 indeed is also the inferior aspect, aside from the dental for- 

 mula. In ZalopJms the auditory bullae are rather less swollen 

 than in Arctocephalus, but in all other respects there is a strik- 

 ing resemblance. The anteorbital portion of the skull, how- 

 ever, is more attenuated, and relatively much longer. With 

 this exception there is little difference in the general confor- 

 mation of the skull in middle-aged females of these two genera, 

 while both differ widely from Otaria, Uumetopias, and CallorM- 

 nus. The great development of the crests of the skull late in 

 life in ZalopJms gives it at that time a highly peculiar confor- 

 mation. 



