MAMMALIA. 495 



Genus 13 Dxpus. — Cuvier. 



Generic Character. — Incisors ^, no canines, grinders ^^f or ^-|; 

 total IG or 18. Lower incisory teeth sharp pointed ; grinders 

 simple, with tuberculous crowns; eyes large; ears long and 

 pointed ; fore feet short, with four toes, and a tubercle in place 

 of' a thumb, which is furnished with a nail ; the hind feet are 

 five or six times longer than those before, with three or five 

 toes, having one metatarsus for the three middle toes ; tail very 

 long, generally tufted. 



Diptts sigitta. — The Common Jerboa. — Plate XV. fig. G. 

 — Described, vol. II. p. 542. See also vol. II. p. 339. 



Genus 14. — Gerbillus. — Desmarest. 



Generic Character. — Incisors |, no canines, grinders |-5 ; to- 

 tal IG. Grinders tuberculous ; the first with three, the second 

 with two, and the third with one tubercle ; ears moderately sized ; 

 fore feet short, with four toes, and a rudimentary thumb ; the 

 hind legs very long, having five toes with nails ; each foot with 

 a proper metatarsal bone ; tail long, covered with hair. 



Gerbillus Canadensis — The Canada Gereil. — Plate XV*. 

 fig. 11. — Fur yellowish above, white underneath; ears short; 

 tail with hardly any hair, somewhat longer than the body ; with- 

 out any tuft. Inhabits Canada, in the neighbourhood of Quebec 



Genus 15. — Aspalax. — Desmarest. 



Generic Character. — Incisors \, no canines, grinders |-| ; to- 

 tal 16. Incisory teeth large ; square at top and bottom ; those 

 in the under jaw twice the length of the upper ones ; grinders 

 with tuberculous crowns ; body long, cylindrical ; eyes very 

 small, concealed by the skin ; no external ears ; feet short, with 

 five toes ; tail naked ; fur short and soft. 



Aspalax typhlus. — The Spalax. — Plate XVI*. fig. I- — 

 Ym blackish ash colour at the base, reddish towards the point ; 

 head large and thick ; the whole animal cylindrical ; eyes con- 

 cealed by the fur. About eight inches long. Inhabits Asia 

 Minor, Syria, Mesopotamia, Persia, and Southern Russia. 

 This is the mole of the ancients. There is a variety with irre- 

 gular white spots. 



