There are three or four diltincl fpecies, or at leaf! 

 permanent varieties of Jerboa, and in the Hiftory of 

 Quadrupeds of Mr. Pennant they conftitute a parti- 

 cular genus ; but Linn.^us places them as fpecies of 

 the genus Mus. 



The Jerboas are animals of the mod furprizing fwift- 

 nefs, and on the approach of danger immediately 

 fpring forward by fucceffive leaps, fo very nimbly, that 

 it is faid to be very difficult for a man well mounted to 

 overtake them. They are impatient of cold, and re- 

 main during the winter in a dormant ftate in their bur- 

 rows. They feed on vegetables. The particular fpe- 

 cies here reprefented differs principally from the com- 

 mon Jerboa or Mus Jaculus of LiNN^su^ in having the 

 legs furnifhed at a little diftance above the feet with a 

 pair of fpurious toes or fpurs. It is found not only in 

 the warmer regions of Barbary and Syria, but in the 

 Eaftern part of Siberia in confiderable plenty. It is 

 about the fize of a lar^e rat. 



