veio Neotropical Muridre. 357 



Oryzomys Stolzmanni, sp. n. 

 Hesperomys lonyicaudatus, Thos. P. Z. S. 1882, p. 104 fnec Benn.). 

 In size and proportions clearly belonging to the 0. lonrji- 

 caudatus group. Fur of medium length, rather close and 

 stiff. General colour dark rufous brown, finelj lined with 

 black, the resulting tone approximately similar to " Front's 

 brown " of Ridgway. Head greyer and less rufous. Ears 

 rather small, laid forwards in a spirit-specimen they reach 

 just to the middle of the eye ; brown, finely mixed with 

 rufous, not prominently darker than the general colour. 

 Palate-ridges 3 — 5. Chin white ; chest and belly dull bufFy 

 yellow, the bases of the hairs slate. Upper surface of hands 

 and feet white ; fifth hind toe, without claw, reaching to the 

 end of the first phalanx of the fourth. Tail very long, finely 

 haired, uniformly dark brown throughout, or the underside 

 faintly paler. Mammte 2 — 2 = 8. 



ISkull very much as in 0. longicaudatuSy but the edges of 

 the interorbital region seem to be rather more evenly concave 

 and the palatal foramina are shorter, not reaching to the level 

 of the front of ^^. 



Dimensions of the type (measured as a spirit-specimen in 

 1882):— 



Head and body 82 millira. ; tail (from anus) 137 ; liind 

 foot 22*5 ; ear (of a specimen now in spirit) 12 x 10 ; forearm 

 and hand "26. 



Skull : greatest length 25"5, basilar length 19 ; nasals 9'2 

 X 2'8 ; interorbital breadth 3'7; interparietal 3x9; palate 

 length from henselion 101 ; diastema 6*4; palatal foramina 

 4'3xl'5; length of upper molar series '6'6. Lower jaw: 

 condyle to incisor-tip l4*3 ; coronoid to angle 6*4 ; height 

 of ramus below ^^-^ 3. 



Hob. Huambo, N. Peru, 3700 feet. Coll. Dr. J. Stolz- 

 mann, April 1880. 



Type : Specimen b of the list given, P. Z. S. 1882, p. 104. 

 B.M. 81.9.7.11. 



This species is distinguishable from typical 0. longicau- 

 datus by its darker back, buff-coloured belly, and shorter feet. 

 Tomes's description of Idesperotitys minutus from Pallatanga, 

 Ecuador, based on a young specimen, would have prevented 

 my giving a name to this mouse had it not been that the 

 Museum possesses an adult from the same place which agrees 

 sufficiently well with that description to be in all probability 

 the same species. This animal differs from 0. Stolzmanni 

 by its much more rufous coloration, above and below, and by 

 the almost complete suppression of the projecting plate of the 

 anterior zygoma-root. 



