184 U.S. NATIONAL MUSEUM BULLETIN 2 75 



texture, formed of both brown and white hairs, and extending caudad 

 beyond the level of the ears; scapular regions, upper arms, and pectoral 

 areas with moderate suffusions of buff ; forefeet white dorsally, almost 

 naked ventrally, and with five digits bearing claws; hind feet white 

 dorsally and with five digits bearing dark-colored claws; plantar sur- 

 faces heavily furred except for a small naked area on the ventral 

 surface of the heel; tail, dorsally, approaching color of body and 

 heavily suffused with brown-tipped hairs, and ventrally near Pale 

 Pinkish Buff; a distinct brownish pencil occupying the distal one- 

 fourth of the dorsal surface of the tail. Skull: Relatively small in size, 

 auditory bullae short and well inflated ventrally; anterior palatine 

 foramina relatively narrow ; meatal expansion of auditory bullae with 

 abrupt curvature and not applied to the squamous process of the 

 temporal bone; suprameatal triangle rounded and with posterior 

 processes imperfectly closed. 



Comparisons. The type series of Meriones libycus auratus can be 

 easily distinguished from near topotypes of Meriones libycus libycus 

 from the West Desert region of Egypt by markedly smaller and less 

 robust crania, smaller overall size, especially the small size of the hind 

 feet, and noticeably paler, more golden dorsal color. 



Members of this subspecies resemble rather closely those of Meriones 

 libycus azizi from farther north and east in Cyrenaica but differ in 

 having larger hind feet, wider interorbital breadths and rostra, and 

 paler, more golden dorsal pelage with more prominent postauricular 

 and supraorbital patches. 



Remarks. Representatives of this subspecies throughout coastal 

 Libya are remarkably uniform in color and cranial characters. Two 

 specimens, 321835 and 321836, from 40 kilometers east-northeast of 

 Nalut on the Tripolitanian coastal plain are almost indistinguishable 

 from those from the type locality in Cyrenaica, and specimens from 

 El Agheila on the southern margin of the Gulf of Sirte do not differ 

 appreciably from topotypes of M. I. auratus. This morphological 

 homogeneity is the result of constant genetic exchange within and 

 between populations of these jirds rendered possible by the almost 

 uninterrupted continuity of suitable habitat of the Cyrenaican and 

 Tripolitanian coastal plains. 



Setzer (1956) referred two specimens from El Agheila and a single 

 specimen from near Zliten to Meriones libycus confalonierii (= Meri- 

 ones caudatus confalonierii). These three specimens are specifically 

 different from the other specimens found in these localities and clearly 

 belong to Meriones libycus auratus. Regardless of their taxonomic 

 status at that time this erroneous assignment is unaccountable as the 

 two forms are easily separable: in the field, by the more bushy tail 

 with prominent black pencil of M. caudatus and in the laboratory, by 



