164 Mr. 0. Thomas on 



white, of feet dull white with a darker area along the outer 

 side of the metatarsus, but this area is not sharply contrasted 

 as is sometimes the case. Tail little longer than the head 

 and body, well-haired, uniformly blackish above and below, 

 the proximal inch below only inconspicuously lighter. 



Skull thin and papery, without strong ridges. Palatal 

 foramina reaching to the level of the second lamina of m^. 

 Bullae comparatively small. 



Dimensions of the type (measured in the flesh) : — 



Head and body 59 mm. ; tail 70 ; hind foot (s. u.) 16-5 ; 

 ear 12"5. 



Skull: greatest length 21; basilar length 15; length ot 

 nasals 7"8 ; interorbital breadth 3-5 ; breadth of brain- 

 case 10'5 ; palatal foramina 4'6 ; length of upper molar 

 series 3*3. 



Ilah. Jinotega, Nicaragua. Altitude 4650'. 



Tyjje, Adult male. Original number 29. Collected 20th 

 January, 1906, by Mr. M. G. Palmer. 



This Eeithrodontomys is distinguishable by its small size, 

 short ears, dull coloration, and short unicolor tail. 



Mr. W. H. Osgood has been kind enough to compare this 

 mouse with the specimens in the U.S. Department of Agri- 

 culture collection, and he tells me that it does not appear to 

 resemble very closely any of the species there. ''It is, 

 perhaps, nearest to R. australis of Costa llica, but is darker 

 on the upper parts, slightly smaller, and the tail is shorter 

 and more nearly unicolor." 



Ctenomys Steinbachtj sp. n. 



A fairly large species, of a uniform coppery-grey colour. 



Size rather above the average in the genus. Fur straight, 

 fine and glossy; hairs of back about 13 mm. in length. 

 General colour a peculiar dark drabby grey-brown or coppery, 

 quite unlike that of any known Ctenomys, but very similar 

 to that of certain Geomyidas, e. g. Zygogeomys trichopuSy 

 Merriam. This colour is quite uniform over the Avhole of 

 the head, upper surface, and sides. Under surface creamy 

 white, the hairs dull slaty for their basal two thirds; line of 

 demarcation on sides fairly sharply defined. Whiskers white. 

 Chin and a band across the lower neck in front of the arms 

 brown, separated by a broad whitish patch running across 

 the interramial region and narrowing on the sides to a point 

 about half an inch below each ear. Arms and legs light- 

 coloured, except a narrow band running down the front of 

 the forearms; hands and feet almost naked above, pale 

 brown, the lateral fringes whitish. Tail very thinly clothed, 

 its sparse hairs dull white. 



