Article V. DESCRIPTIONS OF NEW RODENTS 

 FROM SOUTHERN PATAGONIA, WITH A NOTE 

 ON THE GENUS EUNEOMYS COUES, AND AN 

 ADDENDUM TO ARTICLE IV, ON SIBERIAN 

 MAMMALS. 



By J. A. ALLEN. 



In preparing my report on the mammals collected by the 

 Princeton University Expeditions to Patagonia, 1896-1899, 

 under the direction of Mr. J. B. Hatcher, the following 

 additional species x have been found which appear to be 

 undescribed. A more detailed account of them, with 

 illustrations, will appear later in the final report on the 

 collection, now nearly ready for publication. 



The genus Ctenomys is represented in southern Patagonia 

 by at least five well-marked forms, three of which appear to 

 be new. Reithrodon and Euneomys are each represented by 

 several forms, three of which have not been previously recog- 

 nized. In working out these species, represented by abun- 

 dant material, it has been found that Euneomys is not very 

 closely related to Reithrodon, and equally distinct from Phyl- 

 lotis, when properly restricted. 



Ctenomys robustus, sp. nov. 



Type, No. 84194, U. S. Nat. Mus., $ ad., Rio Chico de Santa Cruz, 

 near the Cordilleras, Feb. 20, 1897; O. A. Peterson. 



Pelage soft, short, somewhat lustrous. Above deep yellowish 

 brown, varied with blackish, the hairs being dark slaty plumbeous 

 for the basal two thirds, with a subterminal band of dark rusty yellow, 

 and a very short black tip, with longer blackish- tipped hairs sparsely 

 intermixed; below deep brownish ochraceous; ears dusky brown, 

 barely projecting above the fur; upper surface of fore and hind feet 

 dingy yellowish gray; tail well clothed with fine soft hairs,. forming a 

 slight pencil at the tip, yellowish gray, dusky at the tip above. 



Other specimens vary from the above in being a little lighter or a 

 little darker, both above and below. Tail variable in color, often 

 wholly without any dusky median line above or any dusky tip ; gener- 



1 EHgmodontia morgani, based on specimens in the present collection, was described in 

 1 90 1 (Cf. this Bulletin, Vol. XIV, p. 409). 



