I 914 ] Taylor: Aquatic Adaptation in the Carnivora 471 



much more conservative, remarking 15 that the hind limbs are de- 

 veloped into flipper-like organs, similar to those of some seals. 

 He notes the general likeness of the sknlls of the seal and sea- 

 otter, and says: "In general superficial aspects, the Sea Otter 

 is not unlike a Seal, a resemblance increased by the flipper-like 

 hind feet." Cones is apparently the first author who clearly 

 discriminates between superficial resemblances to the seal and 

 the real and close affinities with the rest of the otters. 



Gill 10 divides the subfamilies of the Mustelidae into two 

 groups, the first including the Mustelinae, Mellivorinae, Melinae, 

 Helectidinae, Zorillinae, and Mephitinae, and the second includ- 

 ing the Lutrinae and Enhydrinae. 



His characterization of the two groups follows : 



"1. — Skull with the cerebral portion comparatively compressed back- 

 wards; and with the rostral portion comparatively produced, attenuated 

 and transversally convex above; anteorbital foramen small, and opening 

 forwards. Feet with little-developed or no interdigital membrane. 



"2. — Skull with the cerebral portion swollen backwards and out- 

 wards; and with the rostral portion abbreviated, high and truncated 

 forwards, and widened and depressed above; anteorbital foramen en- 

 larged, and produced downwards and backwards. Feet with well- 

 developed interdigital membrane, and adapted for swimming." 



It will be noted that the fundamental resemblances of the 

 sea and river otters are presented in the characters of group 2. 



According to Gill's classification, the Enhydrinae are separ- 

 ated from the Lutrinae on the basis of the tooth formula and the 

 elongation of the digits of the posterior feet. 



The characters mentioned above under the second group serve 

 to hold Gill's two subfamilies (Lutrinae and Enhydrinae) to- 

 gether in a broad way. Other common characters are (and these, 

 of course, are more intangible) the general similarity in shape of 

 body, length of tail, and habits. 



With the possible exception of the digits of the hind feet, 

 every part of the skeleton of Latax clearly resembles in general 

 form and shape the corresponding part of Lutra. The differ- 

 ences elaborated below rest on close scrutiny and comparison. 



is Coues, E., op. ext., pp. 325, 327. 



is Gill, T., "Synoptical tables of characters of the sub-divisions of 

 mammals, with a catalogue of the genera." Smithsonian Inst., Misc. 

 Collect., vol. 11 (1871), pp. 64, 65. 



