1914] Taylor: Aquatic Adaptation in the Carnivora 477 



The orbit in the two skulls of the sea-otter is relatively (to the 

 length of the skull) larger than in the Lutra canadensis. This 

 enlargement may be due to an increase in size of the visual organ 

 to adapt the animal for sight under water, paralleling the con- 

 ditions in this respect observed by J. C. Merriam 23 and others in 

 iehthyosaurs, in which group the orbits of the later Jurassic 

 forms are larger than in the earlier Triassic reptiles. The relative 

 enlargement of the skull of Latax lutris may also be definitely 



Fig. 3. Skull of Lutra canadensis (Univ. Calif. Col. Palae. ) x%. 

 Fig. 4. Skull of Latax lutris (no. 8124, Univ. Calif. Col. Palae.) X%. 



related to aquatic adaptation. The later iehthyosaurs, those 

 which had lived longest in the water, had larger skulls relatively 

 to the length of the trunk than those of earlier periods. As an 

 extreme example of this kind of skull modification, the whales, 

 in which the proportionate size of the skull is tremendous, may 

 be cited. 



25 Merriam, J. C, "Triassic iehthyosauria, with special reference to 

 the American forms," Mem. Univ. Calif., vol. 1 (1908), p. 74. 



