112 



MAMMALIA ORDER V.RODENTIA. 



nutrias it is a sign that it never dries up in a drought. But during the 

 drought which prevailed during the time I was in the country, some places 



inhabited by nutrias did dry up, but it 

 was probably many years since they had 

 done so previously. In the steep banks 

 of the lagunas the nutrias make drives, 

 the mouths of the tunnels being half in 

 and half out of the water when it is at its 

 normal height. The nutria is not a very 

 shy animal. Some of them inhabited a 

 little water-course by the side of which 

 the sheep-dipping place was situated ; 

 they were probably attracted by tho 



Fig. e2.-Covru(Myopotamv,coypu'). head of water kept up by a small dam. 



The nutria swims with hardly a ripple, 



and disappears noiselessly in the dive at the water-line. The body is dull 

 brown, muzzle greyish, and there is a little warm brown on the side of the 

 head. It swims with the nose, tho top of the head, and a narrow line of 

 the back out of water, all on a dead level, or almost so ; the nostrils being 

 very high up in the line of the skull, they are kept out of the water without 

 the nose being poked up towards the sky. A half -grown one brought to me 

 alive ate green maize readily." 



In the West Indies the family is represented by the large arboreal Rodents 

 known as hutias, most of which are included in the genus Capromys, although, 

 on account of the more complex structure of its molars, one species from 

 Hayti and Jamaica is separated as Plagiodon. 

 They may be compared to gigantic rats, one of 

 them measuring 22 inches to the root of the 

 tail. Their incisors are narrower than those 

 of the coypu, the first genus having one inner 

 and two outer folds of enamel in the upper 

 molars. From both the above the two species of 

 cane-rat (Thrynomys) 1 from Southern Africa 

 are at once distinguished by the presence of 

 three deep grooves in each of the upper 

 incisors. The small American forms consti- 

 tuting the genera Echinomys and Loncheres are sufficiently characterised 

 by generally having flat, lance-shaped spines intermingled with the fur ; 

 most of the species being inhabitants of Brazil and Guiana, although one of 

 the second genus is found in Central America. The South American 

 Mesomys differs from Loncheres in having a short, curved claw on the first toe 

 of the fore-foot, as well as in the absence of spines. The single and rare 

 species of the Brazilian genus Dactylomys is characterised by its short ears, 

 long scaly tail, the rudimental first toe of the fore-foot, the very long third 

 and fourth toes of the same, which are furnished with short, convex nails, 

 the flat incisors, and the division of the molars into two complete lobes, 

 each of which has a single enamel-fold, forming a fork-shaped grinding 

 surface ; as well as by the two series of upper cheek teeth converging so 

 much as to meet in front. A smaller Brazilian form known as Canna- 

 bateomys differs by the union of the two lobes of the molars by means of a 

 bridge of enamel, and the slight convergence of the teeth. Another South 

 1 To replace the preoccupied name Aulacodus. 



Fig. 63. HUTIA (Capromys). 



