neto Neotropical Muridas. 359 



riparius, altliougli not so finely grizzled as in the latter. 

 Below, the yellowish tips to the hairs gradually beco.ne dirty 

 white, the slaty-grey bases of the hairs still showing through. 

 Palate-ridges 3 — 5. Ears of medium length, almost naked, 

 their anterior prominence little developed. Upper surface of 

 hands and feet dull whitish brown ; hfth hind toe, without 

 claw, reaching just beyond the base of the fourth; pads small, 

 rounded, distinct. Tail short, tapering, nearly naked ; its 

 upper surface brown, its lower very slightly paler. Mamrafe 

 2—2 = 8. 



Skull thick and strongly built; nasals long, parallel-sided; 

 supraorbital edges strongly diverging, sharply edged, with a 

 fine bead along them ; interparietal of moderate size ; outer wall 

 of anteorbital foramen long, convex forwards; palatine foramina 

 unusually large and open, the breadth across both of them 

 almost half their length. Molars small, but very much 

 worn down in the type. 



Dimensions of an aged female in spirit : — 

 Head and body 115niillim. ; tail 84 ; hind foot 24"o; ear 

 16x13; forearm and hand 28; heel to front of last foot- 

 pad 11. 



Skull : greatest length 29' 7, basal length 24*8, basilar length 

 23, greatest breadth 16; nasals, length 13, greatest breadth 

 8'7 ; interorbital breadth 4*7 ; interparietal, length 2"3, breadth 

 8'5 ; palatal length from henselion 12*6 ; diastema 8*1 ; pala- 

 tine foramina, length 6*3, breadth 3 ; length of upper molar 

 series (c.) 4*1. Lower jaw : condyle to incisor-tip 19*6 ; 

 height of ramus below ^ri 4'5. 



Hah. Surinam. Coll. E. Bartlett. 

 Ti/pe: B.M. No. 66.8.11.16. 



This is one of the species which make the subdivision of 

 the group into genera so difficult. In all its characters except 

 the shortness of its tail it is a true Oryzomys ; but in this 

 respect it approaches Acodon, especially through such species 

 as A. punctulatus^ which has beaded supraorbital edges. 

 However, in view of its general skull-structure, it seems best 

 for the present to call it an Oryzomys^ directing attention at 

 the same time to its Acodont external proportions. 



Oryzomys (?) venustus, sp. n. 



Size small, tail short ; ears rather large. Fur very long, 

 soft and fine ; on the back the hairs are about 13 millim. in 

 length. General colour soft drab {Ridgivay) on the back, 

 lightening to sandy buff on the sides, the tips of the hairs 

 being buff finely lined with blackish. Face like sides. 



