312 3k[r. O. Thomas on new Neotropical 



Proechimys Warreni, sp. n. 



A small species related to P. Cherriei, Thos. 



Size quite small, as in P. Cherriei^ the hind foot con- 

 spicuously shorter than in the better-known species of the 

 P. trinitatis group. Spines thick and strong, about 1-3 mm. 

 broad by 19 ram. long, very numerous on the back, but 

 practically absent on tlie rump and lower flanks. General 

 colour of the usual dark fulvous, heavily lined witli blackish, 

 the hairs with fulvous subterminal rings, and the spines 

 greyish white basally, black terminally. Head more greyish 

 brown. Under surface pure sharply defined snowy white, as 

 are the hips and inner sides of the limbs. Areas along inner 

 aspect of forearms and of lower leg thinly haired, almost 

 naked. Upper sides of hands and feet white. Tail fulvous 

 like body for its basal inch, then blackish brown above and 

 white below, the two colours more sharply separated than in 

 P. Cherriei; thinly haired, the hairs two or three scales iu 

 length. 



Skull very like that of P. Cherriei, agreeing with it in size 

 and in the smoothness of the brain-case, there being, even in 

 the oldest specimens, no trace of ridges running across the 

 parietals. But the palatal foramina are much shorter, widely 

 open mesially, tapering posteriorly as well as anteriorly, 

 ending further from the molars, and without any raised 

 parallel ridges leading back from their edges towards the 

 front oip". Pterygoid processes spatulate, about 0*8 mm. broad 

 at their basal neck, broadening out to 2 mm. at their widest 

 point ; in P. Cherriei they are almost equally narrow through- 

 out (0-8 mm. at the neck, I'O mm. at broadest point). 



Molars rather small, all quadrilaminate as usual. 



Dimensions of the type (measured in the flesli) : — 



Head and body 228 mm. ; tail 185 ; hind foot (s. u.) 41 ; 

 ear 25. 



Skull : greatest length 51 ; basilar length 36-8 ; greatest 

 breadth 24*5; nasals 19-5 ; interorbital breadth 11*3 ; cUasteraa 

 16-2 ; palatal foramina 5'1 X 3 ; length of upper cheek- 

 tooth series 7. 



Hah. Comackka, 80 miles up the Demerara River, British 

 Guiana. Alt. 50 feet. 



Type. Old male. Original number 17. Collected 1st 

 July, 1905, by Mr. S. B. Warren. Five specimens. 



This series of old and young specimens is of interest as 

 confirming the status of P. Cherriei, which was founded on a 

 single specimen, whose small size and smooth skull suggested 

 youth, though the molars were fully worn. From the 



