504 On Mammals from the Bahr-el-Ghazal. 



16. Arvicanthis sp. 



f^ . 34, 35, 38. Between Cliak Chak and Deni Zubeir. 

 7/9. iii. 07. 



17. Thamnomys MacmilJani^ sp. n. 



cJ.21,25. Chak Chak. 24. ii. 07. 



A small Thamnomys of the T. arborarius group. 



Size as in T. arborarius. 



Fur soft and silky, about 10 mm. long on back. 



General colour above a dark " olive-buff," with a good 

 deal of ochraceous colouring on the median line, especially 

 bright on the rump, basal three fourths of hairs dark slate ; 

 underside pure white, the iiairs white to their bases. Feet 

 ])ale buff. Tail dark, ))ale below for basal half; 17 rings = 

 10 mm.; sparsely clothed with dark hairs; iiairs short for 

 basal half of tail, then lengthening to 3-4 mm. on terminal 

 fourth. 



Skull and teeth as in T. arborarius, but markedly smaller 

 in all details judging from Peters's description and figure. 



Dimensions of type : — 



Head and body 102 mm. ; tail IfiO; hind foot 22; ear 1,5. 



Skull: greatest length 28; basilar length 21; greatest 

 breadth 13*5 ; nasals 9'5 ; interorbital breadth 4*3 ; brain-case 

 breadth 12 ; diastema 6*7 ; length of upper molar series 4'3; 

 bulla3 5. 



llab. Wouida, N. of Lake Rudolf. Alt. 6200'. 



Type. Adult female. B.M. no. 6. 11. 1. 38. Taken by 

 Mr. Zaphiro on the 30tli June, 1905, and presented to the 

 British Museum by Mr. W. N. McMillan. 



Two specimens sent by Mr. Butler from Chak Chak are 

 quite like the type in all essential characteristics (their skulls 

 unfortunately are imperfect). The colour-pattern is also 

 similar, but the grey-drab shoulder-patches are even more 

 clearly marked in Mr. Butler's specimens. 



18. Thryonomys Swinderenianus^ Temm. 

 Skull only. Chak Chak. 1. iii. 07. 



19. Gazelli albonotata, Roths. 



No specimen of this striking species had hitherto been 

 obtained by the National Museum. 



