192 U.S. NATIONAL MUSEUM BULLETIN 2 75 



Psammomys obesus tripolitanus Thomas 



Psammomys tripolitanus Thomas, Proc. Zool. Soc. London, pt. 2, p. 9, 1902 (Bon 

 Cheifa, on the coast, Cyrenaica, Libya). 



Specimens examined. Six, from Cyrenaica: Gheminez, 1; 20 km 

 SW Agedabia, 1 ; 10 km S Agedabia 3; 5 km W El Agheila, 1. 



Measurements. Measurements of an adult female, 325630, from 

 20 kilometers southwest of Agedabia, are: Total length 300; length of 

 tail 127; length of hind foot 34; length of ear 14; greatest length of 

 skull 41.3; length of auditory bulla 14.7; alveolar length of upper 

 molariform toothrow 7; least interorbital breadth 6.9; length of 

 nasals 15.7; breadth of rostrum at level of antorbital foramina 4.5; 

 greatest breadth across zygomatic arches 24.7; least breadth between 

 parietal ridges 1 1 . 



Diagnosis. Same as for P. o. obesus, except dorsum with stronger 

 suffusion of brownish hairs, and skull smaller and more gracile. 



Comparisons. Compared to representatives of P. o. obesus from 

 near Tobruch and Bardia, Cyrenaica, and near topotypes of P. o. 

 obesus from Burg el Arab and El Daba, Western Desert Governorate, 

 and Damanhur and Hofs, Beheira Province, Egypt, the few specimens 

 from the coastal plain of the Gulf of Sirte are smaller in overall size 

 of skull, have wider interorbital breadths, wider rostra, shorter 

 anterior palatine foramina, and are darker in dorsal color. 



Because the range of P. o. obesus is interposed between the ranges 

 of P. o. tripolitanus and those of Psammomys obesus nicolli from the 

 Nile Delta and Psammomys obesus terraesanctae from Palestine, critical 

 comparison with the two latter subspecies was not undertaken, but 

 from cursory examination both P. o. nicolli and P. o. terraesanctae 

 appear to be significantly larger both cranially and in external size 

 and dimensions. Psammomys obesus nicolli is also darker in color, 

 whereas P. o. terraesanctae is noticeably paler and more uniformly 

 colored than P. o. tripolitanus. 



Remarks. Topotypes of P. o. tripolitanus are not available for study, 

 but because the specimens from Gheminez and the vicinity of Agedabia 

 agree closely with the description and measurements of P. o. tripolitanus 

 as given by Thomas (1902), and because of geographic proximity, 

 they are here referred to this subspecies. 



Psammomys vexillaris vexillaris Thomas 



Psammomys vexillaris Thomas, Ann. Mag. Nat. Hist., ser. 9, vol. 16, p. 198, 

 July 1925 (Bondjem [=Bu Ngem], Tripolitania). 



General distribution of species. Libya and Algeria. 



Distribution in Libya. At present, this species is known from only 

 the vicinity of the type locality. The range probably includes most of 

 the coastal plain and the transitional deserts of Tripolitania. 



