from the Neotropical Region. 305 



face. Interorbital region flat, its edges square, not heavily 

 ridged. Palatal foramina rather narrow for the group, ex- 

 tending backward to the level of the front of ^li. Bulloe 

 rather, though not measurably, larger than in the allied 

 species of the group. 



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



Head and body 113 millim, ; tail 125, with terminal tuft 

 141 ; hind foot (moistened) 24; ear (dry) 14. 



Skull : basal length 25'7 ; basilar length from henselion 

 23-8; greatest breadth 16*6; nasals 10"5x3*7; interorbital 

 breadth 4-3, interparietal 4-lxl0'6; palate length from 

 henselion 12*8; diastema 8; palatine foramina 6*2x2*2; 

 length of upper molar series 4*7. Lower jaw : condyle to 

 incisor-tip 18*8. 



Hob. Agua Dulce, W. Cundinamarca, Colombia. 



Type collected Sept. 19, 1895. 



This pretty Vesper-rat differs from all other members of 

 RMpidomys by its slate-mixed fulvous belly, this part being 

 in the other species perfectly pure white. A very young 

 specimen from Fanabista corresponds in all respects with the 

 old one. 



Oryzomys niveipes, sp. n. 



General appearance remarkably like 0. laniger^ Thos., 

 although it is slightly larger. Fur very long, soft, and 

 fluffy. General colour dull olive-fulvous, darker mesially 

 above, clearer and paler along the sides and below ; line of 

 demarcation on sides indistinct. Hairs everywhere above and 

 below slate-coloured basally. Ears large, well-haired, black. 

 Hands and feet silvery white above, without darker meta- 

 tarsals. Tail long, thinly haired, brown above, paler below. 



Skull very different from that of 0. laniger. Face long 

 and slender, with a narrow muzzle and long, narrow, parallel- 

 sided interorbital region, whose edges are rounded and not 

 ridged. Brain-case smoothly rounded, not broad in propor- 

 tion to its length. Zygomatic plate little projected forward. 

 Palatal foramina reaching just past the anterior end of ^. 



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



Head and body 113 millim.; tail 140; hind foot 26; 

 ear 18. 



Skull: basal length 26'8; basilar length from henselion 

 25; greatest breadth 16; nasals 12*4 x 3*8; interorbital 

 breadth 4, interparietal 3*5 x 10*5 ; palate length from hen- 

 selion 13*2 ; diastema 8*7; palatal foramina 7x2*4; length 

 of upper molar series 5. Lower jaw : condyle to incisor- 

 tip 19*5. 



