650 



Bulletin American Museum of Natural History. [Vol. XXIV, 



This genus is characterized externally by the abundance and strength of 

 the spines, which occupy nearly the whole of the dorsum and nearly conceal 



the underlying fur. The enamel 

 pattern of the molariform teeth 

 presents four strong, deep, oblique 

 furrows instead of three short, shal- 

 low, transverse furrows as in Pro- 

 echimys ; the same differences char- 

 acterize the lower molariform se- 

 ries, except that m 3 has only three 

 furro\vs instead of four, as in the 

 other teeth. These differences are 



Fig. !.__ Hoplomys truei. 



Type. No. 28367, 

 The last molar only slightly worn, f . 



well shown in the accompanying 

 figures. 



Echimys gymnurus Thomas is to be referred to this genus, and probably 

 also Echimys subspinosus Tomes, both from Ecuador. 



18. Hoplomys truei sp. nov. 



Echimys centralis ALLEN, Bull. Am. Mus. Nat. Hist., IX, 1897, 42, Costa Rica 

 (not of Thomas, 1896). 



Type, No. 28367, c? ad., Lavala, Matagalpa Province, Nicaragua, Oct. 5, 1907. 



General color of upper parts black- 

 ish varied with pale rusty brown; 

 flanks grayish brown; whole ventral 

 area pure white ; f orelimbs dusky gray- 

 ish brown, the toes lighter; hind feet 

 buffy white, more or less edged and 

 mottled with dusky brown ; soles of all 

 the feet blackish brown; ears nearly 

 naked, dark brown passing into black- 

 ish apically; tail wholly naked and 

 coarsely scaled, grayish brown above, 

 whitish below. Head and body, 380 

 (type) and 400 mm.; tail, 170 (type) 

 and 140; hind foot 50 (type) and 45 



(collector's measurements) ; hind foot, 



Fig. 2. Proechimys trinitatis. Type species of 

 the genus Proechimys and type skull of the spe- 

 cies. No. 6018, 9 ad. 



The teeth are slightly more worn than in the 

 skull of Hoplomys shown in Fig. 1, but the attri- 

 tion has not changed the pattern of the crown 

 surface of the teeth, f. 



with claw (in dry skin), 53 (type) and 

 51. Skull (type), occipito-nasal length, 

 55; zygomatic breadth, 27; mastoid 

 breadth, 21 ; length of nasals, 20, upper 

 molariform series, 10; lower, 10.5. 



This species closely resembles in coloration Echimys semispinosus 

 Tomes, 1 from "Ecuador" (exact locality not known, 2 but probably from 



1 Proc. Zool. Soc. London, 1860, p. 265, fig. 1-4, skull. 



2 Thomas, Ann. and Mag. Nat. Hist. (6), XX, Dec. 1897, p. 551. 



