RODENTS OF LIBYA 143 



because of their diminutive size, warrant reinstatement as a distinct 

 subspecies. 



Within series of these gerbils, all gradations of body size are noted, 

 ranging in length from 230 mm to well below 200 mm. This wide 

 range may reflect degenerative changes in the genotype of the popu- 

 lation engendered by the agency of "drift" resulting from a long 

 period of absolute physical isolation without any outbreeding with 

 marginal populations. Specimens from nearby Bzema and Tazerbo 

 Oases, although similar in color to those from Cufra, are clearly re- 

 ferable in their larger size and cranial characters to G. c. dodsoni and 

 show no evidences of gene exchange with G. c. patrizii. 



An adult male, 325348, from El Hauuari, is uniformly gray and 

 lacks the typical variegated character of the dorsal pelage. This 

 specimen probably represents an aberration in color without any 

 genetic significance. 



Ecological observations. The series from both El Hauuari and 

 El Giof were collected among sedges and other mesophytic plants that 

 occur as a fringe of dark green vegetation surrounding the low-lying 

 saline lakes in the interior of these oases. In most areas, these sedges 

 form almost impenetrable masses; consequently, trapping is usually 

 limited to the periphery of the habitat. In these areas the substrate 

 is extremely hard and impregnated with salts from adjoining lakes. 

 These gerbils were never taken from the sandy areas of the oases 

 proper. In these areas, Gerbillus gerbillus and Acomys cahirinus are 

 the dominant rodents. 



Gerbillus campestris wassifi Setzer 



Gerbillus campestris wassifi Setzer, Journ. Egypt. Publ. Health Assoc, vol. 33 

 no. 6, pp. 209-211, 1958 (Libyan Plateau, near Salum, ±200 ft., Western 

 Desert Governorate, Egypt). 



Specimens examined. Five (1 skin only), from 5 km W Bardia, 

 Cyrenaica Province, Libya. 



Measurements. Measurements of an adult male, 325509, from 

 the above locality are: Total length 245; length of tail 135; length of 

 hind foot 30; length of ear 17; occipitonasal length of skull 30.4; 

 length of auditory bulla 9.3; crown length of upper molariform tooth- 

 row 4.1; greatest breadth across zygomatic arches 16; least inter- 

 orbital breadth 5.5; breadth of rostrum at level of antorbital foramina 

 3.2; length of nasals 12. 



Diagnosis. Dorsum Ochraceous-Tawny becoming lighter on sides 

 and rostral areas, all parts with strong suffusions of darker hairs; 

 pre- and postauricular spots and supraorbital patches conspicuous and 

 white with faint admixture of bmTy hairs; pectoral areas with indis- 

 tinct buffy patch; eye ring black; cireumoral areas, dorsal surfaces 

 of forelegs, hindlegs, feet, and entire underparts white; ventral surface 



