140 Mr. O. Thomas on 



Skull : f^reatest length 32 5 ; basilar len;i;th 24*3 ; zyo;o- 

 niaticbrea'lth 14"2 ; nasals \lr> x \ ; iiiterorbital breadth 5 6; 

 breadth of brain-case 13'2 ; palate leni^th 12"2 ; diastema 7*3 ; 

 palatal foramina 7x 2*6; length of upper molar series 4"9. 



JLth. High Paramos surrounding sources of Rio Seeurd. 

 Type from Choquecamate, -4000 m. 



Ttipe ]\Iale. Original number 1504. Collected I5t!i 

 July, 1901. 



"On grassy plain." "In stone wall." "Native name 

 ' Huacucha.' "—P. 0. S. 



This species differs from the one it most resembles — 

 0. liuberti of Minas Geraes — by its smaller size, longer and 

 softer fur, and tlie presence of the longer tine hairs on its 

 posterior back; but its general api)earance is very similar, 

 and the two no doubt represent each other in these widely 

 separated localities. 



While O.juliacce is the Oxymi/cterus of the low valleys 

 bordering on the Amazonian plains, 0. parnmeii'<is represents 

 the genus on the Andean iiighlands. No member of the 

 genus has hitherto been recorded from so great an altitule. 



The Clioro specimens are rather larger than the others, but 

 do not seem specifically separable. 



25. Oxyviycteras juliacce, Allen. 



2 S- Charuplaya, 1350 m. 21st ]\Iay to 22nd June, 

 1901. 



Originally described from the Inambari River. 



26. Proechimys securus, sp. n. 



2 c?, 4 ? • Charuplaya, 1350-1400 m. June 1901. 



Allied to P. bolioiunus^ Thos., but with shorter feet. 



Size rather small. General colour, as usual, dark fulvous, 

 heavily lined with black on the back. Sides rather clearer, 

 the edges of the belly lined, especially in the younger 

 specimens, with a line of bright buffy ; but this is absent in 

 the type. Under surface white, fairly well defined laterally. 

 Head browner than back. Ears naked, greyish brown; the 

 tufts at their anterior bases dark brown. Upper surface of 

 Ijands and feet dull whitish bio.vn. Tail, as usual, finely 

 haired, not pencilled, brown above, white below. 



Skull, like the foot, short in proportion to the siz'i of the 

 animal, low and squat. Ascompared with that of P. bolivianusy 

 the nasals are broader, with slightly convex lateral edges, 

 the intentrbital space is proportionally broader and is flatter 

 and less strongly ridged. Supraorbital edges evenly curving 



