RODENTIA. 149 



fore feet, and in certain species, besides the three great toes to the 

 hind feet, there are small lateral ones. They live in burrows, and 

 become torpid during the winter. 



B. sagitta; 31. sagitta, L. ; Buff. Supp. VI, xxxix and xl. 

 The Jerboa has only three toes, and is the size of a Rat; a 

 light fawn colour above ; white beneath ; tuft of the tail black, 

 the tip white. Is found from Barbary to the north of the Cas- 

 pian sea. 



D. hertipes, Licht. (The Hairy-footed Jerboa.) The head 

 more compressed ; only three toes to the hind feet, as in the 

 Jerboa, but they are more hairy. From Africa. (1) 



D.jaculus; M.jaculus, FM. Glir. XX, Schreb. CCXXVIII. 

 (The Alactaga.) Two small lateral toes ; ears longer than 

 those of the Jerboa, but is nearly of the same colour. Pallas 

 has observed them of three sizes, from that of a Rabbit to that 

 of a Rat: they are probably as many species. (2) One or the 

 other is found from Barbary to the Eastern Ocean, and as far 

 as the north of India. 



Helamys, F. Cuv. Pedetes, Illig.(3) 



The Jumping Hares, like the Jerboas, have a large head, and 

 great eyes, a long tail, and the anterior part of the body extremely 

 small, in comparison to the posterior, although the disproportion is 

 much less than in the true Gerboas. The peculiar characters of the 

 Helamys are four grinders every where, each one composed of two 

 laminae ; five toes to the fore-feet, armed with long and pointed nails, 

 and four to their great hind ones, all separate, even to the bones of 

 the metatarsus, and terminated by large nails, almost resembling 

 hoofs. This number of toes is the inverse of that most common 

 among the Rats. Their inferior incisors are truncated, and not 

 pointed like those of the true Jerboas, and of the greater part of 

 the animals comprised under the genus of Rats. One species only 

 is known, the 



H. caffer.^ Mus.cqff'er.,Fa.\l.] Bipus caffer., Gm., Buff. Supp. 

 VI, xli, and better, Fred. Cuv. Mammif. It is the size of a 

 Hare, of a light fawn colour, and has a long tufted tail, with a 

 black tip. Inhabits deep burrows at the Cape of Good Hope. (4) 



(1) Add the Bip. telum, D. platurus, and D. lagopus of Eversman, Voy. de 

 Mayendorf en Boucarie, p. 390. 



(2) Pallas has latterly distinguished the small Alactagasby the name of Dip. 

 acontion. 



(3) Pedeies, jumper, Helamys, Jumping'-Rat. 



(4) See Append. XI of dm. Ed. 



