Mammals from Lake Ngami, &c. 399 



It is interesting to note that Mr. Woosnam obtained four 

 specimens of this species near the Molopo River, not very far 

 north of Kuruman, the type locality o£ S. hildce, Schwann. 

 S. hildce, compared with this new series of S. anderssoni, 

 appears as a very much darker animal, especially noticeable 

 in the young specimens, the young of 8. anderssoni being 

 rather paler than the adults, while in S. hildce they are a 

 good deal darker. 



u I found this mouse plentiful on the rocky banks of the 

 Molopo River and at several places in the Kalahari up to 

 Ngamiland. One was caught on an island in the middle of 

 the Okovango marshes. They feed largely on the beans 

 of the kameel-thorn (Acacia) trees.'" 



24. Arvicanthis pumilio deserti, subsp. n. 



? . 13. Lehutitung, Kalahari. 



$ (in spirit). Kakia, Kalahari. 



A pale sandy-coloured form allied to Arvicanthis pumilio 

 griquo?, Wrought. 



Size and general proportions as in A. p. griquos. General 

 colour of upper surface pale sandy yellow (between putty- 

 colour no. 3 and pale ecru no. 3, 'Repertoire de Couleurs'), 

 rather paler on the flanks and sides of head. Dorsal stripes 

 much fainter and less evident than in A. p. griguce, light 

 orange-brown in colour ; the two median stripes not pro- 

 longed forwards on to head. Ears covered with short 

 orange-coloured hairs ; no well-marked dark margin to ears. 

 Backs of hands and feet yellowish white. Entire underparts 

 white, washed with greyish buff. Tail light brownish yellow 

 above; underside white. 



Skull larger than that of A. p. griguce, with rather larger 

 auditory bullse, flatter and broader brain-case, and broader 

 nasals. Molar teeth rather larger than in A. p. griguce. 



Dimensions of the type (measured in the flesh) : — 



Head and body 115 mm.; tail 116; hind foot 22-25 ; 

 ear 14. 



Skull : greatest length 29"9 ; basal length 26 ; condylo- 

 basal length 27"9; basilar length 243 ; condylo-basilar 

 length 26; zygomatic breadth 14*9; breadth of brain-case 

 across squamosal region 12'6; interorbital breadth 4*7; 

 nasals, greatest length 11, greatest breadth 3 - 6, least 

 breadth 1*5; palatal length 14*5; palatilar length 12*5; 

 width of palate inside m 1 2*5 ; width of palate outside w 1 

 5*9 ; length of palatal foramina 6 ; post-palatal length 

 11*3; length of upper cheek-teeth 5. 



