342 Mr. G. Dollinan oii Arvicantliis aLyssiuicus 



Type locality. Egypt. 



This species appears to be fairly generally distributed in 

 Northern Egypt ; the Museum collection contains specimens 

 from Cairo, (jiza, and theFayoum. The specimens from the 

 latter locality represent the species described by Lichtenstein 

 as Ilypudceus variegatus, and are quite similar to the Cairo 

 specimens of niloticus ; thus the name variegatus must be 

 regarded as a synonym o£ niloticus, and not as referring to 

 any member of the testiciilaris group. 



Mus discolor, Wagner, is founded on a bleached specimen 

 of niloticus, the hind foot, which measures some 36 mm. in 

 length, showing its relation with the large-footed Egyptian 

 species. Tlie type locality is given as Lower Egypt, so 

 there is no difficulty in regarding discolor merely as a 

 synonym of niloticus. 



(6) Arvicantliis abyssinicus, Riipp. 

 Mua abyssinicus, Riippell, Mus. Senck. iii. p. 104, pi. vii. fig. 1 (1S42). 



A medium-sized species, greyish olive in colour, with 

 dorsal stripe usually distinct and tail comparatively short. 



Size of body a great deal less than in niloticus, averaging 

 only 145 mm. in length ; hind foot rather small (27 mm.), 

 tail short. General colour of dorsal surface greyish olive, 

 lined with black and washed over with buff, the general effect 

 somewhat similar to that of niloticus, but lighter and more 

 finely speckled. Flanks rather paler than back. Dorsal 

 stripe usually well marked, though in many cases it is almost 

 lost amidst the black speckling on the back, especially in 

 bleached individuals. Light markings under and behind ears 

 well marked, more so than in any other species; this feature 

 is especially noticeable in the juvenile pelaiic, an account of 

 which is given below under A. zapliiri. Face with butly ocular 

 rings and yellow'ish-orange nasal region. Backs of hands 

 and feet dirty white, tinted with pale buff. Underparts 

 brownish or greyish white mixed with bufl' ; ventral surface 

 not differentiated at all from flanks, the general colour of the 

 flanks gradually passing into the mixed brownish or greyish 

 white of the belly. Tail short and rather more hairy than 

 in many of the subspecies ; dark above, i)ale butfy white 

 below. 



Skull smaller than in testicularis or niloticus. Zygoma 

 exj)anded, not markedly so in the squamosal region. Brain- 

 case short and broad. Auditory lullre rather more inflated 

 than in the preceding species. Teeth comjiaratively largo ; 

 molar scries equal in size to those of testicularis. 



