ORDER RODENTIA. 149 



serves as a resting point when they fall to the ground, and 

 a helm during their leap, or rather flight. 



They sometimes walk on the four paws, but it is only 

 when they are uneasy, or when they are digging their bur- 

 rows. They often hop like birds. They carry their provision 

 to their mouth with their fore-paws. 



It is difficult to preserve these animals in captivity, unless 

 they receive a sufficient quantity of earth or sand to dig into. 

 They may be subsisted on carrots, fruits, cabbage, bread, 

 fyc. They never drink, and yet urinate abundantly. 



The Arabs, Tartars," and Calmucs find the flesh of the 

 Alactaga a dainty, and employ themselves greatly in the 

 chase of this quadruped. The Burats and Monguls have 

 fallen into an erroneous opinion that this animal sucks 

 their sheep by night. 



The Gerboa Brachyura, Dipus Brachyurus of M. De 

 Blainville, is Pallas's second variety of the Mus Jaculus. 

 The size is intermediate between the Alactaga and Little 

 Gerboa. The muzzle is less elongated than in the first of 

 these animals. The mustachios and ears are shorter, and 

 the last are wider. The cylindrical tail, thicker and shorter 

 in proportion, is terminated by a tuft, the hairs of which 

 are not so exactly distinguished, and the white part is less 

 extended. The hind-feet are also relatively shorter, with 

 more robust toes, and the nail of the middle toe less long 

 than those of the lateral toes. 



The size of this animal, when adult, and the epiphyses of 

 the bones are completely united, is nearly equal to that of 

 the Common Rat, while the dimensions of the Alactaga 

 approach to those of the Squirrel, and the Little Gerboa is 

 not much beyond the Mus Sylvaticus in size. 



In proportion and size, this variety approximates very 

 nearly to the Mus Sagitta or Gerbo, but differs in the 

 number of toes. In this respect it is analogous to the 

 Alactaga and Little Gerboa. It has four distinct toes, and 



