488 PROCEEDINGS OF THE NATIONAL MUSEUM vol. io8 



The skull, thoiigli, is so badly brok(Mi tliat no measurements can be 

 taken that would be reliable. 



In color and from what remains of the skull, the above specimens 

 agree in all respects and in no way seem to vary from the species 

 gerbillus except in the minor characters which are used as criteria for 

 subspecies. 



Gerbillus gerbillus sudanensis, new subspecies 



Figure 5,a 



Type: BM No. 29.5.19.16, adult male, skin and skull, from Port 

 Sudan, Red Sea Province, Anglo-Egyptian Sudan. Obtained July 28, 

 1928, by E. W. Thomas, original No. 531. 



Specimens Examined: Sixteen, all in BM, from: Kerma, 2; Merowe, 

 1 ; Wad Habushce, near Shendy, 1 ; Khor Mog, 2 ; Khor Hanoieit, 

 5; Port Sudan, 5. 



Diagnosis: Upperparts near Pinkish Cinnamon, purest on sides, 

 flanks, and upper surface of nose. Ears, hands, feet, belly, cheeks 

 to above eyes, postauricular spots, and ventral surface of tail white. 

 Tail brush brownish. Soles of hind feet strongly haired with short 

 white hairs. Skull with short anterior palatine foramina, small 

 molariform teeth, moderately inflated auditory bullae, rostrum 

 relatively short and nariow, nasals relatively short but narrow. 



Measurements of Type Specimen: Length of head and body 80; 

 length of tail 120; length of hind foot 25; length of ear 12; greatest 

 length of skull 26.2; condyloincisive length 22.4; length of anterior 

 palatine foramina 3.7; crow^n length of upper toothrow 3.3; length of 

 auditory bullae 9.9; least interorbital width 5.3; length of nasals 9.9; 

 width of rostrum at level of antorbital foramen 2.8; greatest width 

 across zygomatic arches 14.0; breadth of braincase 13.9. 



Comparisons: From G. g. agag, G. g. sudanensis differs in lighter 

 color, longer tail, and a brownish instead of blackish brush on the tail. 

 The skull is smaller in all respects, the anterior palatine foramina are 

 shorter, the molars are smaller, the rostrum is narrower and shorter, 

 and the auditory bullae are not so inflated. 



G. g. sudanensis may be distinguished from G. g. gerbillus, with 

 which it apparently does not come into contact, by its smaller size 

 and somewhat darker color. 



Remarks: There are no morphological differences between sudanen- 

 sis and agag except in general size. It is for this reason that sudanensis 

 is described as a subspecies of G. gerbillus. No intergradation has 

 been demonstrated, but undoubtedly occurs. 



