RESULTS FROM THE MAMMAL SVR FEY. 643 



parietals 12-4 ; palatilar length 30; palatal foramina 11; upper 

 molars series 10*8 ; breadth of m^ 3-8. 



Hab. — Northern Siam. Type from Chieng-niai. Alt. 306 m. 



r,y|7e.— Young adult female. B. M. No. 9.10.11.24. Original 

 number 249. Collected 25th April 1908 and presented by 

 Th. H. Lyle, Esq. 



The breadth of the first molar in our considerable series of B. 

 nemorivaga never exceeds 3*4 m. 



(C) On the Rat known as Epimyh jeedoni from Upper Burma. 

 By Oldfield Thomas. 



For many years a spinous rat belonging to Bonhote's "jerdoni" 

 group has been known from Upper Burma, and it has been provisio- 

 nally assigned to Blyth's Mus, or Epimys (that is Rathis*) jerdoni. 

 Now however Wroughton has shown that jerdoni itself is a synonym 

 of the earlier fidvescens, and I have therefore made a renewed 

 examination of the Burmese species. 



Although it is closely allied to other members of the same group, 

 it appears to be distinct and requires a special name. I ^^'ou]d 

 propose to call it 



Rattus mentosus, sp. n. 



Most nearly allied to R. confucianus, M. Edw., but smaller ; larger 

 and with longer skull than B. hukit, Bonh. Eur profusely mixed 

 with spines, at least in May, July and Aiigust specimens, probabty 

 less spinous in winter. General colour above greyish brown, suffused 

 with buff}^, the latter colour coming from the tips of the soft hairs, 

 which are worn and at a minimum in the specimens available; pro- 

 iDably in winter the whole upper surface is buffj^, or at least grejash 

 buffy. Undersurface pure sharply defined creamy or buffy white. 

 Ears large, greyish, not contrasted with the head. Hands white, 

 greyish down to the centre of the metacarpals ; feet similar!)^ with 

 some grey on the metatarsals, white on the digits, bxit in some 

 specimens the feet are whollj^ whitish. Tail long, rather coarsely 

 scaled (10 rings to the centimeter), thinly haired, not pencilled, 

 greyish brown above, white below, the white occasionally trespass- 

 ing a little on the tip above. Mammee 2 — 2 = 8. 



Skull shaped much as in confucianus, but larger. Supraorbital 

 bead strongly developed, projecting upwards, continued across the 

 parietals to their posterior third. Zygomatic plate little projected 

 forwards. Palatal foramina of medium length, wide and well open. 

 Bullae small. 



* Cf. Hollister, P. Biol. Soc, Washinoton, XXIX, p. 126, 1916. In ^future th^ 

 word Epimys must be replaced by Rxttus. :: ' 



