196 Annals of the South African Museum. 



Incisors much curved, very stout, about - 2 in. across the tips, 

 chrome-yellow, each with a deep, well-marked groove running its 

 length about one-third of the breadth of the whole tooth from the out- 

 side edge ; lower incisors also stout and chrome-yellow, strongly 

 grooved nearer the outer edge than those of the upper jaw ; the 

 molars consist of a series of parallel laminae of enamel, the number 

 of which to each tooth can be best expressed in the following formula 

 beginning with the anterior tooth : ^Tl^. 



Dimensions (of a skin). Head and body 8'0 ; tail 3'25 ; hind foot 

 I'l ; from ear-opening to tip of nose 1'55. Of a specimen measured 

 in the flesh by Darling (cf. de Winton) ; head and body 7 - 75 ; tail 

 4 - 60 ; hind foot 1'12 ; skull, length 1'60, breath -85 ; upper cheek 

 teeth -40. 



Variation. The Otomys varies a good deal in colour throughout 

 its range, and Mr. Thomas has shown that the specimens from East 

 Africa (Mianzini) and Nyassaland differ from those of the Cape 

 Colony in possessing an extra lamella to the posterior upper and 

 anterior lower molar, making the numbers 7 and 5, instead of 6 and 

 4, as in the typical variety ; in two skulls from Entafufu, in Pondo- 

 land, preserved in the South African Museum the lamella formulae 

 are 'llol-l an d jjEfErj'- The skins belonging to these two skulls do not 

 seem to differ in any very marked respect from the typical variety, 

 and they were both collected in the same locality about the same 

 time, so that until other evidence is forthcoming we may conclude 

 that variation in the number of molar lamellae is not of specific 

 importance. 



Distribution. The Vley Otomys is found over a considerable 

 portion of Africa from Somaliland southwards through British East 

 Africa, German East Africa, Nyassaland, and Angola to South 

 Africa. 



The first collector of this species was M. Delalande, whose speci- 

 mens were described by M. Cuvier under the name of the " Otomie 

 Namaquois," believing that they came from Namaqualand. The 

 South African Museum possesses examples from the neighbour- 

 hood of Cape Town, Bedford, Knysna and Pondoland, and from 

 Potchefstroom in the Transvaal, and it is also recorded from 

 Mashonaland by Mr. de Winton. 



OTOMYS UNISULCATUS, THE BUSH OTOMYS. 



Otomys unisulcatus, F. CUVIEK, Hist. Nat. Mam., livr. 60 (1829) ; 

 SMUTS, Enum. Mam. Cap., p. 46 (1832) ; DE WINTON, Ann. Mag. 

 N. H (7), i., p. 5 (1898) 



