304 Mr. O. Thomas on new Mammals 



its decidedly narrower interorbital region and slenderer muzzle, 

 the same cranial characters also separating it from Rh. lati- 

 manus. 



RMpidomys microtis ^ sp. n. 



A rather small EMpidomys^ with a scarcely pencilled tail 

 and very small ears. 



Fur close and soft. General colour fulvous, duller and less 

 rufous than in the majority of this group ; perhaps nearest to 

 Ridgway's " clay-colour " ; in the centre of the back finely 

 lined with black, clearer on the sides. Under surface white, 

 the hairs white to the roots ; line of demarcation on sides of 

 belly less well defined than usual. Whiskers long and 

 numerous. Ears small and narrow, thinly haired, pale 

 brown. Metapodials brownish, digits dull white, but the 

 difference little marked. Tail long, very finely scaled, uni- 

 formly brown throughout ; scarcely more bushy than in non- 

 Rhipidomyine Vesper-rats. 



Skull of only specimen unfortunately much broken. 

 Muzzle short and narrow, supraorbital ridges sharp. Zygo- 

 matic plate not projected forwards. Anterior palatal foramina 

 long, reaching backwards to the level of the first lamina of 

 2iJ. Molars as usual in the group. 



Dimensions of the type (an adult male in skin) : — 



Head and body 109 millim. ; tail 136 ; hind foot 25 ; 

 ear 12x9. 



Skull : basilar length from henselion (c.) 22 ; nasals 9"6 x 

 3"4 ; interorbital breadth 4'8 ; palate length from henselion 

 11*5; diastema 7*3; anterior palatine foramina 6x2*6; 

 length of upper molar series 4*7. 



Hah. Salina del Vatan, Western Cundinamarca, Co- 

 lombia. 



Type killed Nov. 16, 1895. 



RMpidomys fulviventer^ sp. n. 



About the size of Rh. microtis. Fur very thick and soft. 

 General colour above fulvous, thickly lined with black. 

 Underside clearer fulvous or even bufi", the line of demarca- 

 tion scarcely marked ; hairs of belly slaty grey basally, buffy 

 terminally. Chin and chest whiter. Mammse 1 — 2 = 6. 

 Ears rather small, uniformly brown. Metapodials with the 

 usual piebald patches strongly marked ; digits pure white. 

 Tail long, uniformly brown, not very thickly haired basally, 

 but with a long and well-defined pencil terminally. 



Skull with a large rounded brain-case and slender narrow 



