ANALOGY OF THE COYPtJ. 479 



other peculiarities, we shall no longer be at fault in 

 classification." 



This strange position of the teats is not quite 

 singular, though it has never before been remarked 

 in the Capromys. Mr. Waterhouse in his beautiful 

 work on the Mammalia, now in progress, thus alludes 

 to the subject: — " The female Coypu (a large South 



American Rodent of the same family) 



swims with her young on her back until they are suffi- 

 ciently large to follow the parent. This habit helps 

 to explain the singular position of the nipples in 

 the female Coypu. Of these four were found by 

 M. Lereboullet on each side of the body, and 

 situated rather above the mesial line of the flanks, 

 the foremost being placed behind the shoulder, and 

 the hindermost in front of the thigh." Mr. Water- 

 house considers that this position of the nipples, 

 rather on the sides than the under part of the body, 

 will be found a common circumstance in the Hystri- 

 cine division of Rodents, since he has found them so 

 situated in the genera Lagostomus, Octodon, Ha- 

 hrocoma, and Nelomys. — {Nat. Hist. Mammalia^ 

 ii. 299.) 



The following notes by Mr. Johnston will be read 

 with interest. After a minute detail of some par- 

 ticulars of structure distinguishing the animal from 

 the Cavies, he thus continues : — 



*' The animal treads on the whole of the lower 

 joint of the hind leg, from the hough, as does the 

 rabbit ; it is in fact plantigrade, but its usual motion 

 is very unlike that of either rabbit or rat : the former 

 always, and the latter generally, moving the pairs of 



