1(). AUCTOCEPIIALTJS. 47 



uiulcr-fur. This proves that the Seals from the clifFerent parts of the 

 west coast of America arc distinct from each other, each specimen 

 ha^■ing• a specific geographical range. 



10. ARCTOCEPHALUS. 



Muzzle rather tapering in front. Cutting-teeth -|, upper nearly 

 square. Grinders |^. Palate of the skull rather narrower behind 

 than in front, short, scarcely reaching to the middle of the zygo- 

 matic arch. Lower jaw-bone narrow, rounded below, without any 

 angle behind. 



The face and skull rather elongate ; the forehead flattened, and 

 nearly horizontal from the nasal bone to the vertex ; the palate rather 

 concave, contracted behind, short, not reaching beyond the middle of 

 the zygomatic arch; the nose-aperture large, high; the lower jaws 

 moderate, with a crest-liko ridge behind, beneath, just in front of the 

 condyle. 



The crest-liko process on the hinder part of the under edge of the 

 lower jaw diifers somewhat in shape and development in the different 

 species ; but it nowhere resembles the flat expanded disk found in a 

 similar situation in the lower jaw of the preceding genus. 



Nose simple, with a rather large callous muffle above and between 

 the nostrils. Whiskers cyUndiical, thick, round, tapering, not waved ; 

 hinder ones largest. Ears with a subcylindrical, distinct, external 

 conch. 



Fio-. 17. 



Arctocophalus Ilookeri. Skull, palate, and grinder. 



The fore feet elongate ; the i)alms bald, longitudinally grooved ; 

 claM-s five, very small, rudimentary, scarcely visible. Hind limbs 

 rather produced ; the legs free. The hind feet elongated ; the soles 

 bald, longitudinally grooved ; the toes subequal, short, webbed, and 

 each furnished with a long memliranaceous expansion, the web and 

 the meml)ranaceous expansion bald. 



