314 Mr. O. Thomas on 



Skull-dimensions of the type : — 



Condylo-basal length 67 mm. ; condylo-incisive length 66 ; 

 zygomatic breadth 48*7 ; nasals 25 X 8*7 ; anteorbital fora- 

 men 6*2 x 5 ; greatest breadth on frontals 18*7 ; interorbital 

 breadth 10*5 ; height of crown from alveolus of m* 27*8 ; 

 occipital plane, height from basion 22*5, breadth 33 ; palatilar 

 length 37*2 ; palatal foramina 6*7 ; upper molar series 

 (crowns) 15*2 ; breadth of m 2 5" 6. 



Hob. Eastern Burma and Yunnan. Type from Yunnan, 

 probably from the neighbourhood of Mong-tze. 



Type. Adult female. B.M. no. 12. 7. 25. 42. Original 

 number 4. Collected 9th June, 1910, by H. Orii. 



Distinguished from R. pruinosus by its greater size, this 

 species is separable from R. sinensis by the definitely hoary 

 character of its fur, that animal being practically without the 

 white-tipped longer hairs which give so marked a character 

 to R. pruinosus, latoucliei, and senex. In this respect, there- 

 fore, R. sinensis approaches the unicolor soft-furred Chinese 

 species R. vestitus and davidi. 



Cannomys. 



The uncertainty about the identity of Blyth's Rhizomys 

 castaneus, said to be from " Arakan/' has hitherto prevented 

 consideration of the different species and races of Cannomys. 

 Now, however, the examination of the specimen sent by 

 Dr. Annandale as typical of castaneus * enables me to make 

 a preliminary attempt at the arrangement of the group — but 

 it is very far from complete or satisfactory. 



The specimen of C. castaneus is skull no. 403 of the Indian 

 Museum, and I find it closely agrees with examples in the 

 British Museum from Thaton, Tenasserim, and is clearly 

 the same form. Whether the species is really to be found 

 in Arakan remains to be seen when that little-known country 

 is properly explored. 



Thanks to the splendid work of the Bombay Natural 

 History Society, series of these red bamboo-rats have been 

 obtained on the Chindwin, in the Shan States, and on 

 Mt. Popa, thus effectively supplementing those which the 

 Museum possessed from Sikkim, Manipur, Siam, Tenasserim, 

 &c. 



Externally there is little difference between the different 

 local forms. All are of similar proportions and all; with one 

 exception, have the coat washed terminally with some shade 

 of rufous, which may be brighter in some and deeper in others, 



* Rhizomys castaneus, Blyth, J. A. S. B. xii. p. 1007 (1843). 



