neiv Rodents from ike Orinoco and Ecuador. 381 



surface of hands and feet white. Tail about equal to the 

 body witliout the head, thinly Iiaired, brown above, well- 

 defined white below. 



Skull smooth and rounded, considerably bowed, its lateral 

 profile evenly convex from nasal tip to occiput; supraorbital 

 edges evenly divergent, the beading distinct, running in the 

 usual way to the outer corners of the interparietal ; palatal 

 foramina extending to the anterior third of m\ 



Dimensions of tlie type (an adult male, measured by the 

 collector in the flesh) : — 



Head and body 110 millim. ; tail 38 ; hind foot (s. u.) 20'6 ; 

 ear 17-7. 



Skull: greatest length 30; basilar length 23*5; greatest 

 breadth 15; nasal length J 1"6 ; interorbital breadth 5; inter- 

 parietal 4'lx9; palate length from henselion 12*5 ; dia- 

 stema 8 ; palatal foramina 6"1 X 2*5 ; length of upper molar 

 series 4*2. 



Hah. Maipures, Upper Orinoco. 



Type B.M. no. 99. 9. 11. 39. Original number 11522, 

 collected by Geo. K. and Stella M. Cherrie. 



This species is much smaller than the large Z. brunneusj 

 Thos., and brevicauda, All., rather smaller, with differently 

 shaped skull, broader nasals, and narrower choanal than in 

 Z. microtinuSy Thos., and larger, with heavier feet and more 

 clearly bicolor tail than Hesperomys expidsaSj Lund, of which 

 the British Museum possesses a topotype. 



As I have used it before, I again provisionally use 

 Dr. Allen's generic term Zygodontomys for this group ; but 

 Dr. Forsyth Major has drawn my attention to its close rela- 

 tionship to the typical Hesperomys^ Waterh., as based on 

 H. h'maculatus, and to the possibility that it should hi amal- 

 gamated with that genus. As bearing on the question, the 

 Orinoco species is of particular interest as being intermediate 

 in size and character between the large " Zygodontomys " and 

 the small ^' Helper omys^ 



Echimys Gherriei^ sp. n. 



A small species, with the appearance of a young E. trini- 

 tatis or allied form. 



Size small, form slender. Fur only spinous across the 

 middle back and along a median line extending forwards to 

 the withers ; longest spines of this area about 19 millim. in 

 length by 0'9 in breadth, horny white basally, gradually 

 darkening to black terminally. General colour above coarsely 

 grizzled rufous, very similar to that of E. trinitatis and its 



Ann. & Mag. N. Hint. Ser. 7. Vol. iv. 26 



