510 PROCEEDINGS OF THE NATIONAL MUSEUM vol. loe 



however, fall within the range of variation as noticed for thivS siil)- 

 species. 



Arvicanthis nilolicus lucluosus Dollinan 



Figure &,h 



Arvicanthis luciiiosus DoUman, Aim. Mag. Nat. HLst., ser. 8, vol. 8, p. 339, 

 September 1911. (Kaka, north of Fashoda.) 



Specimens Examined: Six, all in BM, from: 20 miles north of 

 Fashoda, 1; Kaka, 2; Gerazi, 3. 



Measurements: Two adult males from Kaka measm-e, respectively, 

 as follows: Length of head and body 185, 184; length of tail 143, 141 ; 

 length of hind foot 33, 31 ; length of ear 17, 17; greatest length of skull 

 35.5, 35.8; condyloincisive length 33.7, 34.5; length of anterior pala- 

 tine foramina 8.1, 7.5; crown length of upper tootlu-ow 7.0, 6.6; 

 greatest width across zygomatic arches 17.3, 17.6; least interorbital 

 width 5.2, 4.9; length of nasals 13.0, 13.4; width of rostrum at level 

 of antorbital foramen 4.3, 4.3. 



Remarks: When specimens of luctuosus are compared to specimens 

 of A. n. testicularis they are found to be somewhat larger and darker 

 in color. The skull is longer, narrower, with smaller auditory bullae, 

 and with somewhat smaller cheekteeth. 



Arvicanthis niloticus testicularis (Sundevall) 



Figure 6,6 



Isomys testicularis Sundevall, Kongl. Svenska Vet.-Akad. Handl., Stockholm, 

 p. 221, 1843. (Bahr-el-Abiad.) 



Specimens Examined: Forty-nine, all in BM, from: Sennaar, 2; 

 Kamisa, Binder River, 5; Gedaref, 1; El Kowa, 2; Gallabat, 9; Hosh, 

 Blue Nile, 2; Khartoum, 13; Ed Dueim, 2; Kabushiya, 1; Shereik, 4; 

 Nuri, Merowe District, 2; Soba, 1; Shendy, 4; Letti Basin, 1. 



Measurements: An adidt male and an adult female from Kamisa, 

 Binder River, respectively measure as follows: Length of head and 

 body 163, 152; length of tail 143, 146; length of hind foot 31, 31; 

 length of ear 17, 18; greatest length of skull 38.5, 37.6; condyloincisive 

 length 35.6, 35.3; length of anterior palatine foramina 7.8, 7.8; crown 

 length of upper toothi'ow 6.8, 6.7; greatest width across zygomatic 

 arches 20.0, 18.2; least interorbital width 6.3, 6.1; length of nasals 

 15.1, 14.9; width of rostrum at level of antorbital foramen 5.1, 4.9. 



Remarks: The two specimens from Sennaar may be accepted as 

 topotypical. Both specimens are quite faded in color but the skull of 

 the only adult agrees well with the specimens referred to above. 



