1908.] Allen, Mammals from Nicaragua. 651 



the coast). It differs from it in the spines not being "confined to the middle 

 of the back"; neither are they "short and flexible," but long and very rigid. 

 Neither is the tail "pretty evenly sprinkled with shortish hairs," but is 

 entirely naked, the scales coarse, smooth and conspicuous. The skull as 

 figured bears a close general resemblance to that of H . truei, and also to 

 that of P. cent rali* Thomas, especially in the heavy ascending branch of the 

 zygomata, which in H. truei is much narrower in lateral view. The nasals, 

 however, are markedly different from the nasals in either P. centralis or H. 

 truei, they terminating considerably anterior to the premaxillaries. 



In 1897, * I referred a young specimen of spiney rat collected by Mr. A. 

 Alfaro at Suerre, Costa Rica, to Echimys [ = Proechimys] centralis, and 

 later (on the museum label) to E. semispinosus Tomes. It proves, however, 



Fig. 3. Fig. 4. 



Fig. 3. Hoplomys truei. Lower ja\v of skull shown in Fig. 1. f. 

 Fig. 4. Proechimys trinitatis. Lower jaw of skull shown in Fig 2. \. 



to be referable to H. truei, both in external characters and in the tooth 

 pattern. This shows that the range of H. truei extends southward into 

 Costa Rica. It has not been reported from Panama, whence many speci- 

 mens of spiney rats have been received in recent years, all referable to the 

 Proechimys centralis group, except the San Miguel Island form described 

 by Bangs as Lonchcrcs [= Echimys] labilis. This makes the third genus of 

 spiney rats now known from Central America. 



The heavv-spined Echimys gymnurus Thomas, from northern Ecuador, 

 differs radically in coloration from H. truei but agrees with it in tooth pat- 

 tern, in the coarseness of the dorsal spines and (comparatively) hairless tail. 

 It is beyond question a species of Hoplomys. 2 



1 Bull. Amer. MILS. Nat. Hist., IX, p. 42. 



2 On referring to my notes on the Echimyinee made at the British Museum in 1901, I find 

 Echimys gymnurus Thomas indicated as tlic type of a "gen. nov.," with a rough sketch of the 

 tooth pattern. The genus is here first published (see above) as Hoplomys, with H. truei as type, 

 a species congeneric with H. gymnurus. 



