RODENTS OF LIBYA 137 



sometimes extend to forearm; vibrissae relatively long and longer 

 hairs dark brown and lighter ones usually white; pinnae of ears 

 sparsely haired, becoming darker distally, ranging in color from 

 Drab to Fuscous; circumoral areas, dorsal surfaces of forelegs, hind- 

 legs, feet, entire underparts and, in some specimens, ventral surface 

 of tail pure white; fore and hind feet with five digits bearing claws; 

 palmar and plantar surfaces naked, the latter with six metatarsal 

 tubercles; tail medium in length with distal one-third forming prom- 

 inent brownish pencil; tail usually conspicuously bicolored varying 

 from almost pure white to Avellaneous ventrally and from Sayal 

 Brown to Warm Sepia dorsally ; this bicoloration less striking in darker 

 specimens. Skull: Medium in size; frontal bone with a distinct fossa 

 near the nasofrontal suture; zygomata strong and bowing outward 

 posteriorly; braincase flattened; auditory bullae noticeably large and 

 bulbous. 



Comparisons. Compared to a single adult specimen of Gerbillus 

 campestris campestris from near Oran, Algeria, specimens from Brach, 

 Fezzan Province, and Tazerbo Oasis, Cyrenaica Province, are larger 

 in overall size, have markedly longer and more terminally tufted 

 tails, darker, more variable, variegated dorsal color, longer vibrissae, 

 and larger measurable cranial characters. 



In dorsal color, these same specimens resemble topotypes of Gerbillus 

 campestris rozsikae Thomas from Biskra, Algeria but differ from this 

 subspecies in being larger in size of body and cranium and having 

 longer, more conspicuously tufted tails, shorter anterior palatine 

 foramina, and larger, more ventrally inflated auditory bullae. 



For comparisons of these gerbils from Brach and Tazerbo Oases with 

 Gerbillus campestris brunnescens, G. c. wassifi, G. c. haymani, and G. c. 

 patrizii, see accounts of those subspecies. 



Remarks. These specimens from Tazerbo and Brach, although 

 clearly referable to G. c. dodsoni, differ from topotypes of the latter 

 from Ain Hammam, Tripolitania Province, in having slightly darker 

 dorsal coloration, more tufted tails, larger auditory bullae, wider 

 rostra, and slightly wider interorbital region. Other representatives 

 from various localities throughout Cyrenaica, Tripolitania, and the 

 Fezzan also differ from topotypical G. c. dodsoni in subtle characters. 

 These tenuous differences, however, do not exceed the variation 

 expected within populations of the same subspecies. 



In 1902, Thomas described Dipodillus dodsoni {= Gerbillus campes- 

 tris dodsoni) from Ain Hammam, Tripolitania Province, Libya, as 

 distinct from Dipodillus campestris of the coastal areas of Algeria. 

 The two species were distinguished by the larger size, more "desert 

 colour," and more prominently tufted tail of D. dodsoni. He assigned 

 specimens, now known as Gerbillus campestris rozsikae, from Biskra, 



285-134 O — 68 10 



