536 PROCEEDINGS OF THE ACADEMY OF [1896. 



foregoing. Its date, November 12, 1894, would show it to have 

 been taken at Sheikh Mahomet. 



44. Gerbillus sp. ? 



Two examples (No. 3,858,3,929), both females of early maturity, 

 the former taken on the route to, and the latter at. Lake Rudolf, 

 come nearer G. schlegeli than to G. h'ohmi or G. le.ucogader, with 

 which they also seem closely allied. They are darker and smaller 

 than leucogaster, and have much larger audital bullse than bohrni. 



A. Smith considers G. ofer of Gray a synonym of G. schlegeli. In 

 this connection I may remark that the above specimens correspond 

 almost exactly to Smith's plate (pi. 35) of afer in the Illustrations 

 of the Zoology of South Africa. 



45. Gerbillus (sp. nov ?). 



So desperately involved is the nomenclature and classification of 

 the numerous African members of this genus, I hesitate to impose a 

 name on what appears to me an undescribed form, No. 3,857, Ad. 

 9 , from Hargesa, taken July 18, 1894. While resembling, in gen- 

 eral characters of skull and skin, Peters' leucogaster, it is essentially 

 different from any Gerbillus I have examined, in the entire absence 

 of the posterior cusp of m- 3 , that tooth consisting merely of the 

 normal semicircular loop with anterior curve and single posterior 

 crenation. The tooth is not much worn, so that any trace of the 

 posterior cusp would be easily distinguished, neither is there the 

 faintest indication of it at the base of the tooth, the posterior crena- 

 tion nearly reaching the alveolus. 



The specimen is a dry skin ; the upper body colors are a rich, 

 dark fawn, becoming tawny along sides and lined along upper back 

 and head with coarse black-tipped hairs. The ears and upper tail 

 are blackish-fawn, the latter becoming nearly black toward tip and 

 ochraceous white on the lower side. The feet and under side of 

 body, including lower cheeks and upper lips, white to the bases of 

 hairs. Shorter whiskers white, longer ones blackish. Bases of 

 upper body hairs light slate. 



The measurement of the dry skin gives the total length 280 mm. ; 

 the tail, 155 ; the hind foot, 37 ; the ear from crown, 14. The 

 skull is 60 mm. long and 20 wide, the nasals 16 long and very slen- 

 der, the supraorbital bead very strong and with an anterior flange. 

 The ascending ramus of the lower jaw is longer and more erect than 

 in leucogaster and its allies. The audital bullae are large, as in leu- 

 cogaster, but the auditory meatus is compressed. 



