1914] Taylor: Aquatic Adaptation in the Carnivora 467 



long after they took to the water. The ancestry of this species 

 is at least roughly traceable, as its structure shows it to be 

 closely related to the river otter (Lntra canadensis). At the 

 same time, Latax possesses characters which are certainly to be 

 interpreted as incipient adaptations to an exclusively aquatic life. 



The present paper is the result of a study carried forward in 

 continuation of work done by Professor John C. Merriam 1 on 

 the problem of aquatic adaptation as illustrated in the history 

 of certain of the marine reptiles of the Mesozoic, especially the 

 Thalattosauria and Ichthyosauria. 



Pig. 1. Latax Jutris nereis (no. 6956. Univ. Calif. Mtis. Vert. Zool). 

 Drawn from the skin. 



It is intended in this paper (a) to present a detailed discussion 

 of the osteologieal and dental peculiarities of Latax; (6) to 

 submit conclusions from a study of the palaeontologie history of 

 the group; (c) to analyze the characters of Latax, so far as 

 possible, and to consider them in the light of aquatic adaptation ; 

 and (d) to discuss the bearing of the material presented on cur- 

 rent theories of species formation. 



MATEEIAL AND ACKNOWLEDGMENTS 

 Through the interest and generosity of Miss Annie M. Alex- 

 ander a complete specimen of the southern sea-otter, Latax lutris 

 nereis Merriam, C. H., (no. 6956, Univ. Calif. Mus. Vert. Zool., 



i Merriam, J. C, " Triassic Ichthyosauria, with special reference to 

 the American forms," Mem. Univ. Calif., vol. 1 (1908), no. 1; and "The 

 Thalattosauria, a group of marine reptiles from the Triassic of California, ' ' 

 Mem. Calif. Acad. Sci., vol. 5 (1905), no. 1. 



