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U. 8 P. R. R- EXP. AND SURVEYS ZOOLOGY GENERAL REPORT. 



The Scalops aquations differs in several important respects from the species with 44 molars, in 

 addition to its having but 36 teeth and other peculiarities. The muzzle is rather broader and 

 more obtuse than in S. townsendii, although the position and character of the nostrils are similar. 

 The eye is more anterior, and the ear is much smaller. The palms are much broader in pro 

 portion; in fact, with the claws, the dimensions of length and breadth in S. aquaticus are about 

 as they are without them in S. townsendii. The latter species lacks the projecting angle of the 

 inner side of the palm, and the hand is more deeply split between the fingers. The hind foot 

 is shorter and broader at the toes ; the web extends much further along to the claws. The tail 

 is shorter and more thinly clothed with hair. 



Compared with S. breweri, the lateral nostrils, the very thick and densely black-haired tail of 

 the latter, constitute striking features of distinction. The eye of S. brtiveri, also, while similarly 

 situated, is covered by an extension of skin, through which the ball is visible, instead of being 

 concealed. The meatus, too, is much larger than in S. aquaticus; the palms are much smaller 

 and narrower in proportion ; while smaller than in 8. townsendii, their shape and amount of 

 webbing are much as in the last mentioned species, strikingly different from S. aquaticus. 



The species is much more closely allied to 8. argentatus, the article on which I refer to, for the 

 distinctive peculiarities. 



List of specimens. 



