RODENTS OF LIBYA 173 



This coastal subspecies is known from only the type locality at 

 El Agheila, Cyrenaica, and from Marble Arch in Tripolitania. Its 

 range, however, probably includes most of the coastal plain and 

 transitional desert along the Gulf of Sirte as far east as Benghazi. 

 The more mesic uplands of the Cyrenaican Plateau and Gebel Achdar 

 which are interposed between the ranges of this subspecies and that 

 of Meriones caudatus luridus to the east, provide unsuitable habitats 

 for these jirds. The coastal plain also is markedly reduced or absent 

 in many places in northern Cyrenaica and serves to further limit the 

 extent of habitats suitable for jirds and tends to reduce gene flow be- 

 tween the two subspecies. There are no physical barriers separating 

 the range of M. c. confalonierii from that of M. c. caudatus to the south, 

 but apparently the more arid climate farther inland is unsuitable for 

 members of this coastal subspecies. Some intergradation doubtless 

 takes place between these two subspecies somewhere in the transitional 

 desert south of the Gulf of Sirte. 



Ecological observations. This subspecies is apparently confined 

 to the more humid habitats of the coastal plain and littoral deserts 

 surrounding the Gulf of Sirte in Cyrenaica and Tripolitania. The two 

 specimens from near Marble Arch were collected from the northern- 

 most terminus of the coastal hamada overlooking the coastal plain. 

 Vegetative cover here was sporadic, localized, and somewhat transi- 

 tional between that of the more densely vegetated coastal plain and the 

 much sparser plant cover of the hamadas farther inland. Setzer (1957) 

 describes the habitat at El Agheila as consisting of sandy areas with a 

 good vegetative cover. He also observed large, shallow burrows located 

 under bushes and containing from three to eight entrances. Seeds and 

 leaves of locally common plants were found in the burrows. 



Meriones caudatus luridus, new subspecies 



Holotype. Adult male, skin and skull, USNM 325597, from Bahr 

 el Tubat, 21 km ESE Giarabub, Cyrenaica Province, Libya; obtained 

 May 29, 1962, by G. L. Ranck, original no. 2187. 



Specimens examined. Twenty-nine, from Cyrenaica: 11 km E 

 Ain el Gazala, 2; 10 km SW Fort Capuzzo, 1 ; 60 km S Bir el Gobi, 17; 

 Giarabub, 2; Bahr el Tubat, 21 km ESE Giarabub, 5; 24 km SSE 

 Giarabub, 2. 



Measurements. Measurements of an adult male, 325598, from the 

 type locality, and the measurements of an adult female, 302317, 

 from Giarabub, with the measurements of the type in brackets, are, 

 respectively: Total length 268, 240, [291]; length of tail 131, 123, 

 [155]; length of hind foot 34, 32, [36]; length of ear 18, 17, [19]; great- 

 est length of skull 39, 38.6, [40]; length of palate 16.6, 16, [16.3]; 

 length of audital portion of auditory bulla 14.6, 14.5, [15.3]; alveolar 



