THE JERBOA FAMILY. 



161 



of metatarsal bones; in the Alactagas there 

 are three distinct metatarsal bones for each 

 of the three perfect toes, while the two 

 rudimentary toes have none; in the jerboas 

 proper, finally, which have only three toes, 

 the metatarsal bones are fused together into 

 one, which shows at its lower end three 

 rounded pulley -like surfaces for the three 



toes, and thus exactly resembles that of birds. 

 There is, accordingly, a marked tendency 

 to this fusion. The hjnd-toes are always 

 long and armed with erect claws. The 

 jerboas run like long-legged birds, make 

 enormous leaps, and in doing so draw their 

 fore-feet towards their breast or lay them on 

 their cheeks. The tail, usually of considerable 



Fig. 220. — The Cape Jumping-hare {Pedetes coffer), page 162. 



length, serves as a rudder in leaping; except 

 in the jumping-hares (Pedetes) it has only a 

 terminal tuft; in the forms mentioned it is 

 completely covered with hair. The jerboas 

 live in steppes and deserts and are nocturnal 

 in their habits. By day they hide in their 

 holes, which they hollow out with remarkable 

 rapidity. Their food consists of seeds, insects, 

 and the eggs of small birds. The northern 

 species have a deep winter sleep, and with a 

 view to this build a warm nest. 



The Egyptian Jerboa or Common Jerboa 

 of .Northern Africa (Dipus mauritanicus 

 (agyptius)), fig. 218, is the best-known species. 

 It can be abundantly procured in Algeria and 

 Egypt, where it is wide-spread in the desert 



Vol. II. 



tracts. Besides the characters above men- 

 tioned this genus has three cheek-teeth with 

 tubercles and folds of enamel. The head of 

 our species is round and arched, the ears are 

 pretty large, and the whiskers of considerable 

 length; the three toes of the hind-feet are 

 protected against the heat of the sand by 

 small bunches of hair. The fine thick coat 

 of hair has the colour of the sand of the 

 desert. The animal is especially fond of the 

 alfa-covered steppes, lives socially, and digs 

 holes of no great depth, which communicate 

 with one another. In captivity the jerboa 

 is a charming creature, of gentle disposition 

 and very cleanly habits, by no means timid; 

 but it is advisable to keep it in metal cages. 



63 



