172 U.S. NATIONAL MUSEUM BULLETIN 2 75 



deserti; Pachyuromys duprasi; Gerbillus gerbillus; Gerbillus pyramidum; 

 Gerbillus amoenus; Gerbillus eatoni; and Acomys cahirinus. 



Meriones caudatus confalonierii de Beaux 



Meriones libycus confalonierii de Beaux, Ann. Mus. Stor. Nat. Genova, vol. 55, 

 p. 384, 1931 (El Agheila, Cyrenaica Province, Libya). 



Specimens examined. Seven, from Cyrenaica: 5 km W El Agheila, 

 5; from Tripolitania: 15 km WNW Marble Arch, 2. 



Measurements. Measurements of an adult male, 302229, and 

 averages and extremes of four adult females from 5 kilometers west 

 of El Agheila, are, respectively: Total length 277, 280.5 (277-284); 

 length of tail 143, 146.5 (145-148) ; length of hind foot 34, 34.5 (34-36) ; 

 length of ear 18, 18.3 (18-19); greatest length of skull 36.4, 36.8 

 (36-37.4); length of palate 15.3, 15.1 (14.2-15.8); length of audital 

 portion of auditory bulla 13.9, 14.4 (13.7-15); alveolar length of 

 upper molarifocm toothrow 4.9, 5.1 (5-5.3); least interorbital breadth 

 6.4, 6.6 (6.2-6.8); length of nasals 13.5, 13.2 (12.7-13.5); breadth of 

 rostrum at level of antorbital foramina 3.9, 3.8 (3.7-3.9); greatest 

 breadth across zygomatic arches 19.3, 19.8 (19-20.4). 



Diagnosis. Identical to that of Meriones caudatus caudatus as 

 given in the preceding account, except for the slightly paler dorsal 

 pelage with less suffusion of black and the more brownish color of the 

 pencil. Cranially, confalonierii is smaller than caudatus in almost all 

 respects but in general salient features of the skull, there are no 

 significant differences. 



Comparisons. This subspecies can be easily distinguished from both 

 Meriones caudatus amplus of the Fezzan and Meriones caudatus 

 luridus from northeastern Cyrenaica by its markedly smaller, more 

 gracile skull and much smaller overall size of body. 



For detailed comparison with Meriones caudatus caudatus, see under 

 "comparisons" in account of that subspecies. 



Remarks. Most of the specimens considered here are topotypes of 

 Meriones caudatus confalonierii and agree rather closely with measure- 

 ments and descriptions as given by de Beaux (1932) in the original 

 description. 



Setzer (1957) had seven specimens from El Agheila, two of which he 

 erroneously assigned to Meriones libycus confalonierii (= Meriones 

 caudatus confalonierii). He also referred a single specimen (skull only, 

 302311) from Zliten, Tripolitania, to this subspecies. Actually, these 

 three specimens belong to Meriones libycus auratus (then Meriones 

 shawi shawi) and are specifically different from the other five specimens 

 from El Agheila, which were correctly assigned to Meriones libycus 

 confalonierii. The species M. libycus and M. caudatus thus occur 

 sympatrically at El Agheila. 



