RODENTS OF LIBYA 151 



interspersed with numerous brown-tipped hairs which render a 

 variegated or particolored aspect to the pelage; in most specimens 

 Plumbeous underfur exposed dorsally; region surrounding eyes 

 heavily suffused with black and gray, in some specimens extending 

 into subauricular area as a distinct patch; postauricular patches 

 white and somewhat limited in size; rostral area Cinnamon-Buff; 

 vibrissae relatively short, hairs having origin near the eye black 

 whereas those arising nearer the tip of the rostrum white; pinnae of 

 ears short, sparsely haired, Ochraceous-Buff basally and Hair Brown 

 distally and with prominent tufts of silky, buffy hairs arising from 

 the anterior margins; circumoral areas, pectoral region, dorsal sur- 

 faces of forelegs, hindlegs, feet, and entire underparts white; fore 

 and hind feet naked ventrally and each bearing five digits with claws; 

 tail noticeably short, unicolorous, except for suffusions of brown 

 hairs dorsally, and somewhat paler in color than that of the dorsum; 

 a pencil or terminal tuft is lacking. Skull: Small; anterior palatine 

 foramina long and wide; posterior palatine canals distinct and rel- 

 atively wide; auditory bullae small and slightly inflated ventrally; 

 basioccipital present as a rather broad triangular plate between the 

 auditory bullae and forming an elongated foramen on its lateral 

 margins; zygomata relatively fragile; braincase moderately domed; 

 in very old adults a distinct longitudinal fossa present on the medial 

 surface of the frontals extending forward to the level of the infra- 

 orbital foramina. 



Comparisons. Specimens from Libya somewhat resemble a spec- 

 imen (MNHN, no. 1789) of Gerbillus simoni Lataste from Guelt es 

 Stel, Algeria, but differ in noticeably longer tails, less robust skulls, 

 much more fragile zygomata, and paler, shorter, less lustrous fur. 

 Unfortunately, the auditory bullae, which are reputedly of taxonomic 

 significance in distinguishing G. simoni from G. kaiseri, are badly 

 broken in this specimen of G. simoni from Algeria, and comparisons 

 based on this character are not possible. 



Members of this species can be readily distinguished from all other 

 dipodils in Libya by their markedly shorter and almost unicolorous 

 tails and the absence of a well-defined terminal tuft. 



Remarks. Wassif (1956) assigned specimens from coastal Egypt to 

 Gerbillus simoni. This assignment was based on resemblances to the 

 measurements and descriptions of G. simoni as given by Lataste 

 (1881). Prior to this time, no specimens of G. simoni were known from 

 outside Algeria. Earlier, Ellerman (1941) included G. simoni and G. 

 henleyi within the G. simoni group but stated that G. simoni could 

 readily be distinguished from G. henleyi and all other members of the 

 group by its smaller auditory bullae. Later Ellerman (1949) and 

 Ellerman and Morrison-Scott (1951) considered G. simoni as a sub- 



