1906.] MAMMALS FROM BECHUANALAND. 109 



the claws. Tail shorter than the head and body ; covered above 

 and below with short white hair, except on the upper surface for 

 a space of about 10 mm. at the distal end, where it is black ; tip 

 not tufted ; scale-rings numbering about 33 to 1 cm. : mammae 

 three pairs pectoral, and 2 pairs inguinal. 



Skull smooth and rounded, not ridged, No supraorbital edges, 

 only a faint indication of ridges on the parietals. Anterior edge 

 of anteorbital plate shows considerable variation from strong con- 

 vexity to being nearly straight. Palatal foramina widely open, of 

 medium length, ending opposite the anterior lamina of m' ; palate 

 ending 0'5 mm. behind m\ Bullje of medium size. 



Incisoi's not visible beyond the nasals when viewed fi-om above 

 orange in the upper jaw, light yellow in the lower. Molars of 

 medium size, broad with well-defined cusps. Anterior median 

 cusp of m^ larger than the two posterior ones, partly fused with 

 the antero-external cusp. M^ is a simple cu-cular tooth with one 

 large antero-internal cusp. The simplicity of this tooth is very 

 remarkable and quite different from the typical ari'angement 

 found in M. rattus. 



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

 body 138 mm. ; tail 122 ; hind foot 26-5 ; ear 20-5. 



Skull: — Greatest length 35; basilar length 29-4; zygomatic 

 breadth 17-8; nasals 14x3*6; interorbital breadth 4-2; brain- 

 case breadth 13; interparietal 4*4 X 9-4; henselion to back of 

 palate 16-3; palatine foramina 7'6 ; diastema 10; upper molar 

 series 5'7 ; mandible, height at coronoid 10*7 ; incisor tips to con- 

 dyle 24-8. 



Hah. Molopo, Bechuanaland. 



Type. Male. B.M. no. 4.10.1.83. Original number 86. Col- 

 lected 13th July, 1904. 



This very distinct species is unlike any rat hitherto known, 

 both in colour and in the structui'O of the third upper molar. 1 

 have much pleasui-e in naming it after Mr. R. B. Woosnam, to 

 whose efforts in company with Mr. R. E. Dent the British 

 Museum is indebted for this very interesting collection. 



" These rats from Kuruman were trapped in the bush- veldt 

 about half a mile from the river in the mouth of a small hole in 

 a 'wait-a-bit' thorn-bush. Unfoitunately the black ants damaged 

 a good many of the animals in the traps. At Molopo this i-at 

 seemed to be confined to the river pools." — R. B. W. 



19. Mus sp. 



S . D. 132. 2 ■ D- 141. Kuruman. 



c? . W. 74, 75, 84, 89, 22, 93, 100. $ . W. 85, 90. Molopo. 



Owing to the absence of adult females in the series I am unable 

 to ascertain the mammary formula of this animal, a factor of 

 great importance in deciding the specific position of mice in the 

 Mus concha or colonus groujas. 



" These mice are very plentiful among the long dry grass by 

 the Molopo River and in the forest on the banks." — R. B. W. 



