248 ORDER V. 



bed feet, eyes constructed for distinct vision under 

 water ; habits of residence in, and food derived from 

 the watery element ; and these we station in two 

 families, the Otters and Seals. 



Family I. The Enhydridce. Having Musteline 

 'forms and dentition ; but the four feet distinctly 

 webbed ; skull assuming the Phoca character ; sub- 

 marine eyes; constrained movement on land; the 

 articulations in general admitting to form a line 

 with the body ; mostly an habitual residence in 

 fresh waters. 



Genus LUTRA. The River Otters. Incis. , 

 can. \-\, mol. H or f -| =36 or 38. Above the first 

 molar, small, deciduous ; the fourth carnassial mid- 

 dle sized, with two external points and an internal 

 heel ; the fifth with three small external points ; in 

 the lower jaw first molar often wanting, the rest 

 similar to the upper ; all bearing the pointed charac- 

 teristics required for the seizing and retaining a 

 slippery fish -form prey. Body very long ; legs 

 short ; toes 55, webbed ; tail long, powerful, de- 

 pressed, tapering ; close furred ; head depressed ; 

 eyes large, plane ; ears small ; vibrissee very strong ; 

 upper lips covering the lower, and closing it firmly, 

 as in the Phoca ; an anal scent bag ; under the skin 

 a layer of fat, and other approximations to seals.* 



* If we could point out which species have compressed 

 and which depressed tails, and attest the manner of using 

 this organ in swimming, we would have an additional element 

 of distinction. 



