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. : mammte 

 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'*. Bullae of medium size. 



Incisors not visible beyond the nasals when viewed fi'om above, 

 orange in the upper jaw, light yellow in the lowei'. 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 circular tooth with one 

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

 remarkable and quite different from the typical arrangement 

 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 4-4x9'4; 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 structure of the third upper molar. 1 

 have much pleasure in naming it after Mr. R. B. Woosnam, to 

 whose eflforts 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 moiith of a small hole in 

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

 a good many of the animals in the traps. At Molopo this rat 

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



19. Mus sp. 



(S D 132. 5.D. 141. Kuruman. 



S . 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 maminary formula of this animal, a factor of 

 great importance in deciding the specific position of mice in the 

 Mus coucha or colonus groups. 



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

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



