244 Mr. O. Thomas on a new Ecliimys. 



looked for many years, there is a dark brown Ecliimys marked, 

 in ^\ hat appears to be a handwriting similar to that on some ot" 

 Fiaser's labels, '"'' Ecliimys semispinosusy This so precisely 

 agrees with Tcmes's description of that animal, that there can 

 le no reasonable doubt that it is one of the original specimens 

 collected by Fraser and referred to in Tomes's paper. On no 

 other hy}.othesis ran the occurrence of the name, in a hand- 

 writing not that of any English mammalogist, on a specimen 

 fcund in the Zoological Society's rooms be accounted for. 



A comparison of this animal with theNicaraguan, Bo^otan, 

 and Trinidad species shows that it is most nearly allied to 

 the first-named, i'rom which it differs by its much darker 

 colour, its broader nasals (which exceed to a greater extent 

 the premaxillary processes), its parallel-sided palatal foramina, 

 and other cranial details. Its hamular processes are of the 

 same spatulate shape. 



The Bogotau species is, on the other hand, most nearly 

 allied to E. trinitatis, but is specifically different, and may be 

 called 



Echimys chrysaulus, sp. n. 



Size about as in E. trinitatis. Spines, as iu the other 

 members of the present group, restricted to the anterior two 

 thirds of the body, the rump being quite soft-haired. Spines 

 about 15 millim. in length by about 1-3 in greatest breadth. 

 General colour above coarsely mixed yellow and black, tiie 

 lining very heavy, and the contrast between the two colours 

 very marked. Face, sides, and rump more brown and 

 yellowish, producing a very dull tone compared with the rich 

 rufous of E. trinitatis. Under surface pure sharply defined 

 white; no darker half-collar present. Hands and feet 

 white, irregularly mixed with brown along their outer halves. 

 Tail shorter than in E. trinitatis^ fairly well haired, blackish 

 above, white below. 



Skull in many ways very similar to that of E, trinitatis-, 

 the muzzle is, however, broader and more conical (as in cen- 

 tralis and semisjiinosus), the supraorbital ridges, instead of 

 gently curving outwards as they pass backwards, curve 

 abruptly and strongly, attaining over the squamosals a much 

 greater distance apart. Outer corners of interparietal 

 with little ridges running forwards to lose themselves on the 

 surface of the brain- case some way above where those that 

 run back from the supraorbital ledges also disappear. In 

 centralis and scinispinosus these ridges are continuous witii 

 one another ; in trinitatis the interparietal ridges are scarcely 



