142 MAMMALIA. 



Hydromys, Geoff. 



The Hydromys have many external points of relation to the Echi- 

 mys, but they are distinguished from all other Rats by their hind 

 feet, two-thirds of which are palmated^ their two molars have also 

 a peculiar character in the crown, which is divided into obliquely 

 quadrangular lobes, whose summits are hollowed out like the bowl 

 of a spoon. They are aquatic. 



Several of these animals have been sent to Europe from Van 

 Dieman's land, some of which have the belly white, and others 

 fawn coloured, but all of a deep brown above, with a long tail 

 which is black at the base, and the posterior half v/hite. They 

 are sometimes double the size of the brown Rat. Hydromys 

 leucogaster, and Hyd. chrysogaster, Geoff. An. Mus. VI, pi. 

 xxxvi. 



Capromys, Desmar. 



The Houtias have four molars every where with flat crowns, the 

 enamel of which is folded inwards so that it forms three angles on 

 the external edge, and one only on the internal edge of the upper 

 teeth, and the inverse in the lower ones. The tail is round and 

 scantily pilose ; they have, like the Rats, five toes to the hind foot, 

 and four, with the rudiment of a thumb, to the fore feet ; their form 

 is that of a Rat; as large as a Rabbit or Hare. Two species are 

 known. 



Cap. fournieri, Desmar., Mem. de la Soc. d'Hist. Nat. de 

 Par. I, 1823. (The Congo Houtia.)(l) Brown j muzzle and 

 top of the neck whitish; tail brown, but half the length of the 

 body. 



Cap. preliensilis, Posssig. Less than the preceding ; brown, 

 with a whitish throat ; tail red, as long as the body, and partly 

 naked at the end. Both species inhabit the island of Cuba, and 

 together with the .Agoutis, at the time of the discovery, consti- 

 tuted the principal game of the Indians. 



Mus, Cuv. 



The true Rats have three molars every where, of which the ante- 

 rior is the largest; its crown is divided into blunt tubercles, which 

 by being worn, give it the shape of a disk, sloped in various direc- 

 tions; the tail is long and scaly. These animals are very injurious 

 from their fecundity, and the voracity with which they devour every 



(1) This is the Isodon pilondes,Say, Zool. Journ. No. 2, p. 229. 



