

94 MAMMALIA. 



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. 



CAPROMTS, Desmar. 



The Houtlas 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: one is the 



Cap. prehensilis, Poeppig. 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 Hats have three molars every where, of which the anterior is 

 the largest; its crown is divided into blunt tubercles, which, by being worn, 

 give it the shape of a disk, sloped in various directions; the tail is long and 

 scaly. These animals are very injurious from their fecundity, and the 

 voracity with which they devour every thing that comes within their 

 reach. There are three species which have become quite common in our 

 houses, viz. 



M. musculus, L. (The Common Mouse. ) Universally known. 



M. rattus, L. (The Black Rat.) Of which no mention is made by the 

 ancients, and which appears to have entered Europe in the middle century. 

 It is more than double the size of the Mouse in each of its dimensions. 

 The fur is blackish. Several individuals have been occasionally found con- 

 nected by the interlacing of their tails; constituting what the Germans 

 style the King of Rats. 



M. decumanus, Pall. (The Norway or Brown Rat.) Which did not pass 

 into Europe till the eighteenth century, and is now more common in large 

 cities than the Black Rat itself. It is larger than the latter by one-fourth, 

 and differs from it also by its reddish-brown hair.(l) 



These two large species appear to have originated in the East, and have 

 been transported in ships, together with the Mouse, to all parts of the 

 globe. 



GERBILLUS, Desm. 

 The Gerbils have molars that differ very little from those of Rats, merely 



(1) It appears to belong to Persia, where it lives in burrows. It was not 

 till 1727, that, after an earthquake, it arrived at Astracan, by swimming 

 across the Volga. 



