690 CLASS XVII. 



Sp. Pedetes cafer ILLIG., Mus cafer PALL., Dipus Cafer SCHREB., GMEL., 

 Helamys capensis F. Cuv., BUFF. Suppl. vi. PI. 41, pp. 269, 270 (fig. and 

 descrip. of ALLEMAND), SCHREB. Sdugth. Tab. 230, GUERIN Iconogr., 

 Mammif. PI. 28, fig. i ; jumping hare, in South Africa. This animal 

 moves by wide leaps ; it sleeps by day. 



DipUS (ZlMMERMANN, SCHREB., GMEL. in part), ILLIG. (excl. of 



some spec.). Incisor teeth slender, acuminate, the upper grooved. 



q Q 



Molars \ ~ > furnished with roots, complex, with a fold of 

 o o 



enamel sinuate inwards at the surface of crown. Ears not longer 

 than half the head. Fore feet pentadactylous, hind feet tridacty- 

 lous. Tail long, hairy, with tip mostly tufted, and hair set in two 



1 1 11 2 2 



rows (distichous). (Dent. form. OWEN, i. -=- =- , p. ^ - , m. ^ ~ 



1 1 1 1 ^2 ^ 



= 16.) 



Sp. Dipus sagitta GM., SCHREB., Mus sagitta PALL. Glir. Tab. 21 (copied in 

 SCHREB. Sdugth. Tab. 229) ; between the Don and the Wolga, in the South- 

 ern Steppes at the Irtitsch. A very similar species lives in North Africa, 

 Dipus cegyptius LICHTENST., Mus cegyptius HASSELQUIST, which species 

 occurs in Egypt and Barbary, BUFF. Suppl. vi. PL 39, 40, Cuv. R. Ani. t 

 d. ill., Mammif. PI. 60, fig. i. See on the metatarsus, which consists of 

 one bone only, above p. 566. The vertebrae of the short neck have, with 

 the exception of the first, mutually coalesced. See DUVERNOY and LERE- 

 BOULLET M6m. de la Soc. de Strasbourg, in. 1842, PI. m. (skeleton of 

 Dipus mauritanicus, which DUVERNOY distinguishes from D. cegyptius; I 

 observe the same coalescence in the skeleton of a specimen from Egypt). 

 LINN.EUS united the North American and Asiatic species under the name 

 of Musjaculus (Syst. not. ed. 12, I. p. 85). 



Scirtetes WAGN., Alactaga F. Cuv. Incisor teeth smooth; 



4 4 



molars 5 ~ , furnished with roots ; first upper small, cylindric, j 

 o o 



the rest semi-complex with folds of enamel contorted. Feet pen- 

 tadactylous, or hind feet tetradactylous, with three larger toes, 

 insistent, one or two lateral toes raised, small. Ears long, nearly of 

 the length of head, or longer than head. 



Sp. Scirtetes jaculus WAGN., Dipus jaculus PALL., Musjaculus PALL, (not L.) 

 Glir. Tab. 20 (copied in SCHREB. Tab. 228) ; in the steppes between the 

 Donau and the Don and in the Crimea, the Alak-daagha of the Mongols. 

 Here also belong various other species from the steppes on the East coast 

 of the Caspian Sea and at the Sea of Aral, as also a species from North 

 America, Alactaga arundinis F. Cuv. (The molars of this genus, more 



