MAMMALS OBTAINED IN DARFUR. 263 



Tyi^e. xidult female. B.M. No. 23. 1. 1. 218. Original 

 number 1119. Collected 10 February, 1922. 



The members of the genus Dipodillus may be arranged accord- 

 ing to the extent to which the brain-case and bailee are swollen up 

 in proportion to the face, or are of more or less normal Murine 

 development. This species and the much smaller D. henleyi are 

 at the swollen-headed end of the series ; then among Egyptian 

 species follows mncenus ; then stigvionyx with its allies or 

 synonyms luteohis and bottce, and the smaller-toothed watersi. 

 Then comes cccm2Jestris and its ally lowei; and finally, and most 

 extremely murine, the small species next to be described. 



This pretty and distinct species is one of the few novelties 

 resulting from the visit of the Expedition to the black rocky 

 mountain Jebel Maidob, in IST. Darfur, whose mammal fauna 

 has proved far less striking than that of Jebel Maixa. 



41. Dipodillus biuriculus, sp. n. 



c? . 1082. Madu, 80 miles N.E. of El Fasher. 2900'. 



A small species with a very murine-shaped skull. 



Size very small, considerably less than in 2?rinciptdus, little 

 larger than in henlei/i. General external characters as in princi- 

 pulus, except for the markedlj^ shorter tail. Colours as described 

 in princlpulics , with similar white bases to the lateral and anal 

 hairs. The general tone is, however, more strongly buffy, but 

 how far this is affected by the only specimen being tinted with 

 the reddish sand of its locality, we are unable to say. Eye 

 and ear markings present. Hinder soles quite naked. Tail 

 much shorter than in principulus, scarcely pencilled, the proximal 

 portion thinly haired and showing the scales. 



Skull, for a Gerbilline, of a remarkably murine shape, the 

 cranial region neither broadened nor inflated and the bullje small, 

 so that at first sight, at least from above, the skull might be 

 taken for that of a Mus. Supraorbital edges well marked. 

 Palatal foramina narrow. Bullae comparatively small, oval, the 

 mastoid portion almost without inflation. 



Teeth apparently as usual, but much worn in the only specimen. 



Dimensions of the type (measured in the flesh) : — 



Head and body 65 mm. ; tail 82 ; hind foot 18 ; ear 12. 



Skull : greatest length 23 mm. : eondylo-incisive length 20 ; 

 zygomatic breadth 12 ; nasals 8'5 ; interorbital breadth 4 ; greatest 

 breadth of brain-case lO'S ; height from crown to lowest point of 

 bulla 8'8 ; palatal foramina, anterior 3-7, posterior 2'1 ; bulla 

 7"5 X 4"5 ; bi-meatal bi-eadth 10'6 ; upper molar series 3'1. 



Hah. as above. 



Typ)e. Old male. B.M. No. 23. 1. 1. 220. Original number 

 1082. Collected 3 February, 1922. 



A very striking little Gerbil, distinguishable by its short tail 

 and very murine skull. 



18* 



