140 U.S. NATIONAL MUSEUM BULLETIN 2 75 



arches 16, 16.4, 16.5, 16; least interorbital breadth 5.6, 5.4, 5.9, 5.5; 

 breadth of rostrum at level of antorbital foramina 3.1, 3.1, 3.4, 3.3; 

 length of nasals 12.6, 13.2, 12.5, 12.5. 



Diagnosis. Middorsal region Clay Color to Tawny-Olive, becoming 

 paler on sides and flanks and approaching Cinnamon-Buff; entire 

 dorsum with uniform suffusion of brown hairs; circumorbital areas 

 Pale Pinkish Buff, strongly suffused with black hairs; postauricular 

 patches Pale Pinkish Buff; circumoral area, dorsal surfaces of fore and 

 hind feet and legs, and entire underparts white; upper arms with 

 indistinct buffy patch; fore and hind feet each with five digits bearing 

 claws; palmar and plantar surfaces of feet entirely naked, the latter 

 with six metatarsal tubercles; vibrissae relatively long with equal 

 numbers of white and brown hairs; pinnae of ears sparsely haired 

 Ochraceous-Buff basally and Hair Brown distally; tail relatively 

 long and indistinctly bicolored, being somewhat darker dorsally with 

 greater suffusion of brown hairs and with inconspicuous Drab pencil. 

 Skull: Large and robust; zygomata heavy; braincase flattened; 

 auditory bullae large; supraorbital ridges poorly defined; nasals long; 

 and rostrum wide. 



Comparisons. From topotypes of Gerbillus campestris dodsoni from 

 Ain Hammam, Tripolitania Province, Libya, and representatives of 

 G. c. dodsoni from Tazerbo Oasis, Cyrenaica Province, specimens from 

 Bahr el Tubat are paler and more uniform in dorsal color; have longer, 

 less bicolored, and less tufted tails; proportionately smaller and less 

 inflated auditory bullae; and are larger in all measurements. 



Compared to topotypes of Gerbillus campestris haymani from Siwa 

 Oasis, Egypt, specimens from Bahr el Tubat, Cyrenaica Province, 

 have slightly longer tails, smaller ears, slightly shorter molariform 

 teeth, and narrower zygomatic arches. These subtle differences, how- 

 ever, fall well within the range of variation for members of G. c. 

 haymani, and because these specimens from Bahr el Tubat are much 

 larger cranially and in body size from all other contiguous subspecies , 

 they are clearly referable to G. c. haymani. 



For comparisons with G. c. brunnescens, G. c. patrizii, and G. c. 

 wassifi, see accounts of those subspecies. 



Remarks. Hayman (1949), somewhat dubiously, referred specimens 

 from Siwa Oasis in western Egypt to DipodUlus dodsoni but recognized 

 that these specimens differed from typical representatives of DipodUlus 

 dodsoni from Tripolitania Province in having slightly paler and less 

 rufous tails with slaty rather than brownish pencils. Ellerman and 

 Morrison-Scott (1951) assigned these same specimens to Gerbillus 

 campestris campestris and suggested that D. dodsoni was probably a 

 synonym of G. c. campestris and thus extended the range of the 

 nominate subspecies to include most of coastal and interior Libya and 



