new Mammals from Bolivia. 281 



area round the base of the tail. Belly-hairs snowy white 

 terminally, slaty basally. Upper surface of hands and feet 

 well-haired, white. Tail less than half as long as the head 

 and body, well-haired and pencilled, though not to be called 

 bushy, uniformly white throughout. 



Skull (in a rather immature specimen) rounded, not unlike 

 in general outline that of Phyllotis Darwini^ though broader 

 in proportion to its length. Nasals barely reaching forward 

 far enough to hide the incisors ; behind they just surpass the 

 premaxillary processes. Supraorbital edges square (probably 

 sharply so in old age), not beaded or ridged. Interparietal 

 large. Anterior edge of zygoma-root little projecting, evenly 

 slanting forwards. Anterior palatine foramina well open, 

 their edges sharply ridged, their posterior ends level with the 

 anterior lamina of m}. Hinder edge of palate level with the 

 centre of m^, V-shaped instead of transverse, but this may be 

 due to youth. Bullas rather larger than in Phyllotis. 



Teeth. — Incisors narrow, smooth in front, pale yellowish 

 above and below. Molars as described above ; their extreme 

 hypsodontism may be gauged by the fact that the vertical 

 height of the first outer groove on m} is no less than 3 millim. 

 At its broadest point m} is 2*5 millim. in breadth. 



Dimensions of the type (a slightly immature male), mea- 

 sured in skin : — 



Head and body 122 * millim, ; tail 59 ; hind foot, without 

 claws (wet) 26*5, with claws 28 ; ear 23. 



Skull: basal length (c.) 25; basilar length (c.) 24; 

 greatest breadth 16*5; nasals, length 10*7; interorbital 

 breadth 4'8 ; interparietal 3'7 X 12 ; palate length from hen- 

 selion 14 ; diastema 8 ; palatine foramina 6'3 X 2*6 ; length 

 of upper molar series (on alveoli) 72. 



Tij'pe B.M. no. 98. 3. 16. 6 ; original number 1777. Killed 

 June lb, 1897. 



Akodon Berlepschii, sp. n. 



Size and general proportions about as in A. mollis, Thos. 

 Fur thick and close, about 7-9 millim. long on the back. 

 General colour above dark cinereous grey, blacker on the 

 centre of the back, clearer grey along the sides ; no tendency 

 to fulvous, rufous, or olive tones. The hairs of the back are 

 an unusually dark blackish slaty, with a subterminal band of 

 white, succeeded by black tips ; there are also a considerable 

 number of longer black hairs intermixed with the shorter 

 ones. Face like back, no darker markings round eyes. 



* Mr. Garlepp records the total length, including; tail, as 186 millim. 



