390 ME. OLDPIELD THOMAS ON MAMMALS 



This little Squirrel is perhaps merely the representative of N. conchmus in Samar, 

 as it seems probable that there are really two premolars in that animal as in the other 

 Malayan Nannosciuri. The original specimen was described by me as having only one 

 premolar ; but this latter proves on further examination 1 to be the milk-premolar, 

 a fact which renders it rather uncertain whether the adult may not have the additional 

 anterior premolar generally present. 



Apart from this question, N. samaricus may be readily distinguished from N. con- 

 cinnus by its longer fur, much more rufous coloration, and rounder molars. 



"Like the last species, but less often observed." — J. W. 



CeLjEnomys, g. n. 2 



Colour normal. External form as in Chrotomys. 



Shdl (PI. XXXV. fig. 12) broad and strong, evenly rounded, without ridges, very 

 wedge-shaped in lateral view, owing to the great height of the brain-case, and the 

 uniform way in which the fronto-nasal and palatal profiles approach each other 

 anteriorly. Nasals short, not overhanging the incisors. Brain-case smooth and 

 rounded. Interparietal strap-like, fairly well developed. Anteorbital foramen little 

 expanded above, the front edge of its outer plate vertical, not produced forward. 

 Palatal foramina very small. A distinct incisive fissure 3 present, nearly half the size 

 of one of the palatal foramina. Posterior nares broad. Lower edge of mandible 

 peculiarly flattened just behind the symphysis, and pierced with a large number of 

 minute foramina. Coronoid processes long, strongly curved backward. 



Teeth. Incisors much thrown forward, simple, rounded and bevelled in front in a 

 manner similar to that found in Lophuromys. Molars ■§ (PL XXXV. fig. 11), in 

 essential structure like the anterior two of Chrotomys (see below), but the ridges and 

 crests less sharp, although this may be (indeed probably is) due to wear, a point 

 which cannot be settled until young examples are examined. No trace of a third 

 molar either above or below. 



Type. C. silaceus Thos. 



This genus, although it has the same reduced number of teeth as Hydromys and 

 Xeromys, is no doubt really most closely allied to Chrotomys, to which, both in external 

 form and in the general shape of the skull, it presents considerable resemblance. Still, 

 besides the absence of to. 3 , it may be distinguished by its normal coloration, longer 

 and narrower brain-case, and larger interparietal. 



1 Of. Forsyth-Major, P. Z. S. 1S93, pi. xi. fig. 7. 



2 ceXaivos, dark-coloured ; in contradistinction to Chrotomys, derived from xp^s, colour, in allusion to the 

 striking coloration of Chrotomys ivhiteheadi. 



3 By this term I refer to a small mesial opening present, in a great many different forms, between the two 

 premaxillse, just behind the incisors. 



