508 PROCEEDINGS OF THE NATIONAL MUSEUM vol. io6 



est width across zygomatic arches 17.4; least interorbital width 4.4; 

 length of nasals 12.3; width of rostrum at level of antorbital foramen 

 3.9. 



Remarks: This subspecies is a saturate form which differs from 

 other adjacent named kinds as set forth under the comparisons section 

 for D. i. palustris. 



Aryicanthis niloticus centralis Dollman 



FiGUEE 6,6 



Arvicanthis testicularis centralis Dollman, Ann. Mag. Nat. Hist., ser. 8, vol. 8, p. 

 338, September 1911. (BetAveen Chak Chak and Dem Zubeir, Bahr-el- 

 Ghazal.) 



Specimens Examined: Seventeen, all in BM, from: Between Chak 

 Chak and Dem Zubeir, 1 ; Chak Chak, 2 ; Meridi, 3 ; Yei, 1 ; Temburas, 

 1; Kulme, Wadi Aribo, 2; Kurro, Jehel Alarra, 2; Zalingei, 5. 



Measurements: The type, an adult male, measures as follows: 

 Length of head and body 145; length of tail 143; length of hind foot 

 33; length of ear 19; greatest length of skull 37.0; condyloincisive 

 length 34.2; length of anterior palatine foramina 6.6; crown length of 

 upper tootln-ow 6.4; gi'eatest width across zygomatic arcbes 18.5; least 

 interorbital width 5.5; length of nasals 13.7; mdth of rostrum at level 

 of antorbital foramen 4.5. 



Remarks: The specimens from Chak Chak and the type agree in 

 detail. The color is somewhat darker than in kordofonensis and is 

 more uniform or continuous, whereas in the latter the dorsal surface 

 appears somewhat speckled or spotted. The skull in centralis is 

 larger, the anterior palatine foramina are smaller, the auditory bullae 

 are smaller, the zygomatic arches are more flaring posteriorly, and 

 the upper cheekteeth are smaller. 



Intergradation in color, size of upper cheekteeth, and the size of 

 the anterior palatine foramina is found with A. n.jebelae in the animals 

 from Meridi. They are more referable, though, to centralis. 



Arvicanthis niloticus jebelae Heller 



Figure 6,6 



Arvicanthis niloticus jebelae Heller, Smithsonian Misc. Coll., vol. 56, No. 17, p. 

 9, February 28, 1911. (Rhino Camp, Lado Enclave.) 



Specimens Examined: Seventy-seven, from: Nimule, 8 (MCZ); 

 Torit, 29 (6, AICZ); Juba, 1 ; Obbo, 5; Ikoto, 9; Murukm-un, 50 miles 

 east of Torit, 4 CMCZ) ; Bor, 2 (BM); Malek, 11 (BM); Mongalla, 4 

 (BM); Kit River, 3 (BM); Uma River, 1 (BM). 



Measurements: Averages and extremes of three adult males and 

 three adult females from Torit are, respectively, as follows: Length 



