COMMON" JERBOA. 175 



of the rump runs an obscure dusky band, which 

 is probably not a permanent character, since it 

 appears to be more or less distinct in different 

 individuals. The head is short; the ears thin, 

 broad, upright, and rounded : the eyes large, 

 round, and dark coloured: the fore legs about 

 an inch long, with five toes to each foot, the 

 inner toe very small, but furnished with a sharp 

 crooked claw, like the rest : the hind legs are 

 extremely long, thin, sparingly covered with 

 short hair, and very much resemble those of a 

 bird : the hind feet have three toes each, the 

 middle of which is somewhat longer than the rest, 

 and all are furnished with sharp and strong claws : 

 there is also a very small spur or back toe, with its 

 corresponding claw ; but this spur or back toe is 

 so small, that it seems to have been generally over- 

 looked by the describers of the animal ; and it is 

 highly remarkable, that neither Edwards nor 

 Pennant, who both examined this species in a 

 living state, nor even Dr. Pallas, whose accuracy 

 in description is extreme, and who examined a 

 great number of specimens, make the least men- 

 tion of this part ; nor does any vestige of it ap- 

 pear in the figure given by Dr. Pallas of the 

 skeleton. We must, therefore, suppose either that 

 the animal varies in this respect, or that it may 

 perhaps constitute a sexual distinction, and may 

 consequently be found only on some individuals. 

 It may also occur in those which inhabit Barbary, 

 Egypt, and Arabia; but not in those which are 

 found in the sandy deserts between the Tanais 



