I 914 ] Taylor: Aquatic Adaptation in the Carnivora 481 



crushing dentition, for its food would consist of crustaceans, 

 echinoderms and similar animals. Recent Latax represents a 

 genus presumably specialized to this extent, although the exact 

 status of the animal in this respect is not now certainly deter- 

 mined. A recent writer (Snow), 32 whose twenty years of experi- 

 ence hunting the sea-otter lend authority to his statement, asserts 

 that the animal dives to get its food, ordinarily in water of from 

 10 to 25 fathoms depth. As to the nature of the food, Snow states 

 that the examination of hundreds of sea-otter stomachs reveals 

 the fact that crabs, sea-urchins, sea-squirts, and a substance that 

 looked like fish-spawn, are chiefly fed upon. He found no trace 

 of seaweed, clams, limpets or mussels, and very seldom of fish. 

 The crabs and similar animals were chewed up and swallowed 

 shell and all. He says further that the sea-otter is very shy and 

 sensitive, and nowadays rarely comes on shore, though according 

 to accounts given by Steller and others it was formerly in the 

 habit of "hauling out" on the rocks and beaches in large num- 

 bers. 



Further adaptation of our hypothetical species might imply 

 independence of shore animals, and the ability to make use of 

 pelagic forms for food. A simple, subcorneal type of den- 

 tition to serve a prehensile function would be the most advan- 

 tageous at this stage, for the food would consist of such animals 

 as cephalopods and fish. The later Jurassic ichthyosaurs and 

 the modern Phoca approximate this degree of adaptation, al- 

 though this does not imply that phylogenetically the teeth of 

 these forms have passed through a thick, low-crowned stage. 



Neck and Trunk 

 The neck of the animal is very much shorter relatively to 

 length of trunk than in Lutra canadensis. In -this it resembles 

 the seal, which has a proportionately very short neck. In the 

 porpoise (Pliocaota) the shortening has advanced to such a de- 

 gree that the anterior cervical vertebrae are completely fused, 

 and the posterior ones are indicated by thin spines only. In the 

 sea-otter the centra and dorsal arches of the cervical vertebrae 



32 Snow, H. J., In forbidden seas (London, Edward Arnold, 1910), 

 pp. 278-280. 



