RODENTS OF LIBYA 227 



greatest breadth of braincase 18.2 (17.6-18.6), [18.4]; greatest breadth 

 across antorbital processes 23.1 (23-23.1), [23.1]. 



Diagnosis. Upperparts Avellaneous grading into Cinnamon-Buff; 

 supraorbital, interauricular and rostral regions and all parts of dorsum 

 heavily suffused with dark hairs, being particularly concentrated on 

 lateral margins of rump and extending onto flank; sides and scapular 

 region with strong admixture of brownish hairs; entire dorsum thus 

 appearing streaked or variegated in color; mystacial, eircumorbital, 

 and small patches near anterior margin of ear Pale Pinkish Buff; 

 entire underparts white, becoming more buffy on ventrolateral sur- 

 faces; pinna of ear dark (Drab) on distal margins and anteriorly grad- 

 ing to same color as dorsum of body with a thin row of buffy hairs; 

 vibrissae long, almost as long as body, and dark basally; fore and 

 hind feet white dorsally, the former naked ventrally and bearing five 

 claws; soles of hind feet heavily furred with markedly contrasting 

 inner hairs of Mummy Brown and bearing three claws; tail indistinctly 

 bicolored Avellaneous, dorsally, and ventrally, Light Buff, the latter 

 color becoming whiter distally; distal portion of tail distinctly pinnate 

 and bicolored brownish-black proximally and white distally. Skull: 

 Medium, robust, and compacted; incisors large and heavy; upper 

 molariform toothrow long; rostum wide and short; nasals short; 

 zygomata heavy; braincase moderately vaulted; condyloincisive 

 length long; auditory bullae large and markedly inflated; mandible 

 heavy and angular process of mandible with two distinct foramina of 

 nearly equal size on ventrolateral margin. 



Comparisons. Members of this subspecies resemble near topotypes 

 of Jaculus deserti deserti from Biskra, Algeria, but differ in their 

 darker color of dorsum and soles of the hind feet, larger hind feet, 

 larger and more distinct foramina on the angular process of lower 

 jaw and slightly larger size of skull. 



From specimens of Jaculus deserti schliiteri as known from Feiran 

 Oasis, Sinai Governorate, and Wadi Ghuweibba, Eastern Desert 

 Governorate, Egypt, Jaculus deserti Juscipes differs in slightly darker 

 color of dorsum and soles of hind feet, smaller body size, markedly 

 smaller hind feet and ears, shorter skull, smaller and less inflated au- 

 ditory bullae, foramina of angular process larger and more uniform 

 in size, more vaulted braincase, longer molariform toothrow, larger 

 interorbital breadth, shorter nasals, and slightly smaller breadth of 

 braincase. 



Compared with specimens representing Jaculus deserti javillus from 

 20 miles west of Sidi Barrani, Western Desert Governorate, Egypt, 

 this subspecies differs in smaller size of all external measurements, 

 being especially smaller in length of ears and hind feet. In color, 



