550 Mr. 0. Thomas on new 



Hah. Puno, Peru, alt, 4000 metres. 



Tijpe-. B.M. no. 97. 10. 3. 33. Coll. J. Kalinowski, 

 June 15, 1896. 



Of this wonderful and uniquely coloured mouse Mr. Kali- 

 nowski fortunately obtained three specimens. Had there 

 been only one it might have been supposed to be partially 

 albinistic. 



Mr. Kallnowski also obtained in the same district examples 

 of Phyllotis boliviensis, Waterh., Reithrodon pictus, Thos., 

 and Ctenomys opimus^\i' d-g^n. Neither Phyllotisnox Gtenomys 

 had been previously recorded from Peru. 



Echimys gymnurus, sp. n. 

 Size about as in E. semispinosus. Pelage much less 

 uniform in character than in the allied species, the spines, 

 owing to their unusual thickness and length, contrasting 

 markedly with the hairs, not only to the touch, but to the 

 sight ; spines uniformly distributed over the whole of the 

 upper surface, though longer and stronger on the back. 

 General colour deep rich ferruginous, lined witli black, and 

 much broken on the back by the black ends of the dorsal 

 spines; the hairs throughout are dull slaty basaliy, with 

 bright ferruginous tips. Spines of the central back about 

 29 or 30 milllm. in length by 2 millim. in breadth at the 

 broadest part near the base, whence they taper evenly to the 

 strong sharp point ; in colour they are white for their basal 

 and black for their terminal halves^ but on the sides there is 

 a subterminal dusky band, succeeded by a pale reddish tip. 

 Head rather darker than body, the mixture of black and 

 rufous finer. Under surface sharply defined, white from chin 

 to anus, the dark colour approximating a little on each side 

 under the throat. Forearms and upper surface of hands 

 brown, digits almost naked. Legs brown ; metatarsals and 

 digits very thinly covered with silvery hairs. Tail practi- 

 cally naked, the few finer hairs imperceptible witliout a lens, 

 the scales large and prominent; upper surface grey, lower 



white. 



Skull very rugged, with strongly marked ridges and crests ; 

 muzzle long and narrow. Nasals long, evenly tapering back- 

 wards, their hinder edges obliquely truncated, their line of 

 truncation continuous with the oblique hinder edge of the 

 premaxillary processes ; their tip just level with the ascending 

 zygcmatic root. Supraorbital ridges evenly and widely 

 curving outwards, then converging again across the parietals, 

 along which they run as single distinct ridges nearly to the 

 outer corners of the interparietal. Ascending root of zygoma 

 excessively slender when viewed laterally, though more than 



