186 



ALAGTAGA. 



frequent. It Inhabits dry, sandy, and gravelly 

 soils. 



Of this species there are two supposed varieties, 

 agreeing in form with the above mentioned, but 

 differing in size, and in some degree in colour ; 

 but the differences are not such as to justify our 

 considering them as specifically distinct. The 

 first of these varieties is the Middle Siberian Jer- 

 boa, which is of the size of a rat, and has the 

 thighs crossed by a white line; and a whitish 

 zone or circle surrounds the nose. It is found in 

 the eastern deserts of Siberia and Tartary, beyond 

 the lake Baikal. It also occurs in Barbary and 

 Syria, and extends, according to Dr. Pallas, even 

 as far as India. The other variety is called by 

 Mr. Pennant the Pygmy Siberian, Jerboa, It 

 agrees in form with the other, but has no white 

 circle round the nose, and has a smaller tuft to 

 the tail, the end of which is just tipped with 

 white. In size it is far inferior to the middle va- 

 riety. It is said to inhabit the same places witli 

 the large or first described kind. All these agree 

 in their manners, burrowing in hard, clayey 

 ground, not only in high and dry spots, but even 

 in low and salt places ; digging their holes with 

 great celerity with their fore feet and teeth ; thus 

 forming oblique and winding burrows, of some 

 yards in length, and ending in a large hole or 

 receptacle by way of nest, in which are deposited 

 the herbs, &c. on which they feed. They are 

 said to wander about chiefly by night. They 

 sleep rolled up, with the head between the thighs : 



