250 Mr. O. Thomas on 



Tlie liead and scutellnm_, and usually the scutum also, are 

 covered with flat squames, wliich are often refulgent or 

 iridescent. The palpi may be short in both sexes or short in 

 the female only. 



The species are most abundant in the Neotropical region, 

 but also occur in the Ethiopian and Oriental regions and in 

 the outskirts of the Australian region. 



In conclusion, I have to thank Messrs. Austen and 

 Edwards, of the British Museum staff, for the liberty they 

 have given me to examine the collections in their charge and 

 for the many ways in which they have obliged me when I 

 required assistance. 



XXVII. — N'ew Rodents from S. America. 

 By Oldfield Thomas. 



(Pablislied by permission of the Trustees of the Britisli Museum.) 



CEcomys superans^ sp. n. 



A very large species with grey belly. 



Size considerably larger than in any hitherto described 

 CEcomys. 



Fur soft and woolly, but not very long ; hairs of back 

 about 8-9 mm. in length. Ground-colour above greyish 

 rufous, the hairs dark greyish with russet tips ; flanks clearer 

 russet. Under surface pale grey (grey no. 3), the hairs 

 slaty basally, whitish terminally. Ears rather short, brown. 

 Hands with a narrow darker line down the metacarpus, sides 

 and digits wliitish. Feet broad, pale brown above; fifth 

 liind toe reaching to the end of the first phalanx of the 

 fourth ; scutellation of upper surface of feet unusually dis- 

 tinct, the skin of both metatarsus and digits spotted with 

 brown. Tail long, slender, finely scaled (15 rings to the 

 cm.), thinly haired ; brown above and below, or indistinctly 

 mottled with whitish. 



Skull with the large brain-case and shortened anterior 

 zygomatic plate characteristic of CEcomys. Upper outline 

 bowed. Ridges not heavily developed and not showing any 

 indication of postorbital projections. Palatal foramina 

 fairly large and open. Parapterygoid fossse rather broad. 



Molars large and heavy, the anterior end of the series 

 slightly curved outwards. 



