MAMMALS OF ANGLO-EOYPTIAN SUDAN — SETZER 483 



I cannot comment on the species extralimital to the Sudan, but 

 certainly the species found in the Sudan fall into three rather well 

 defined morphological groups. Species in the first group are larger, 

 the bullae are not greatly inflated, the cheekteeth are relatively 

 massive, and the pterygoid fossae are fully open. To this group 

 belong stigmonyx and lowei. Species in the second group are small 

 bodied, the bullae are enormously inflated, the cheekteeth are small, 

 and the pterj^goid fossae are relatively closed owing to the encroach- 

 ment of the anterior ends of the auditory bullae. To this group belong 

 watersi, principulus, muriculus, and mackilligini. 



In no way can I see that stigmonyx and watersi are related, but it is 

 quite evident that principulus and watersi are closely allied and the 

 former may even be only a subspecies of the latter. 



The third group of the subgenus would contain the species bottai, 

 which agrees with neither of the above gi'oups but has minute auditory 

 bullae and quite open pterygoid fossae. The cheekteeth are even 

 more massive in proportion to the size of the skull than in the group 

 characterized by lowei and stigmonyx. 



Since it is apparent that the groups as proposed by Ellerman are 

 untenable for animals of the Sudan, I would propose that the first 

 complex be known as the stigmonyx group; the second as the watersi 

 group; and the thu'd as the bottai group with the characters as given 

 above. 



Gerbillus {Dipodilliis) bottai Lataste 



Figure 4,(i 



Gerbillus bottai Lataste, Le Naturaliste, vol. 4, No. 5, p. 36, Mar. 1, 1882. 

 (Sennaar.) 



Specimens Examined: Two from Sennaar, both in BM. 



AIeasurements: An adult female from Sennaar has no external 

 measurements, but the skull measures as follows: Greatest length 

 22.7; condyloincisive length 19.6; length of anterior palatine foramina 

 3.8; crown length of upper toothrow 3.5; length of auditory bullae 

 7.4; least interorbital width 4.2; length of nasals 7.8; width of rostrum 

 at level of antorbital foramen 2.8. 



Remarks: This is a relatively dark, short-tailed species, resembling 

 in color G. mackilligini but somewhat more pallid. The auditory 

 bullae are extremely minute for a member of the genus, smaller even 

 than in G. muriculus. The skull may be distinguished from all of the 

 other species by the small bullae and the extremely wide-open ptery- 

 goid fossae. The upper cheekteeth are relatively heavy for such a 

 small skull. 



