312 Mr. 0. Thomas on new Mammals 



Hah. Goya, Corrientes, Argentina. 



Collected by Mr. Richard Perrens, May 7, 1896. 



This species is readily distinguished from C. torquatus, the 

 Uruguayan Tuco-tuco, whicii appears to be its nearest ally, 

 by its very differently coloured under surface, less tapering 

 nasals, and more backwardly curved incisors. In colour, 

 especially below, it is very like Waterhouse's G. holiviensisj 

 but is, of course, very far smaller. 



I have named this species in honour of its discoverer, 

 Mr. Richard Perrens, to whom we are indebted for the re- 

 discovery of Azara's " J\Iicouri a queue longue," of which I 

 gave an account in 1894 *. 



G. Perrensi may prove to be Azara's Tuco-tuco ; but that 

 animal has never had a distinctive name applied to it, owing 

 to its identification with the Minas Geraes form, Gtenomys 

 brasilitnsis, de Blainv. 



Lower down the same river-system, at La Plata, another 

 Tuco-tuco occurs, apparently referable to G. minutus^ 

 Nehring. 



Echinomys centralis^ sp. n. 



Both in the Merida and Bogota collections there occur 

 specimens of the genus Echinomys which, on account of their 

 (in comparison with other species) " very dark brown colour " 

 and other characters, may fairly be assigned to E. semi- 

 spinosus. Tomes t, especially if, as seems to be the case, 

 Tomes's woodcut of the skull is incorrect in details. 



But if these are E. semi'spinosus, two examples, clearly 

 different, recently received from Nicaragua, cannot be that 

 animal, and therefore need description as new. 



No doubt they are the same as the examples of " E. semi- 

 spinosus " recorded by Mr. True+ from Greytown, Nicaragua, 

 and from Pacuare, Costa Rica ; so that further details about 

 the species may be gained from his paper. 



Size, as judged by the skull, about as in E. semi'spinosus. 

 General colour much brighter and richer, less heavily black- 

 lined on the back, and with the spineless fur of the sides 

 and rump much brighter rufous. Hands and feet dull 

 whitish above, the darker mark which runs along the outer § 



* Ann. & Mag. Nat. Hist. (6) xiv. p. 184. 



t P. Z. S. 1860, p. 265. 



t P. U. S. Nat. Mus. 1888, p. 467. 



§ Messrs. Allen and Chapman in their description (Bull. Am. Mus. 

 N. H. V. p. 224, 1893) say " inner," but have evidently been misled by 

 the reversed position of the feet in the skins examined. This is a little 



