Rodents from N.W. Yunnan. 517 



This fine vole, wliicli I have named in honour of its 

 discoverer, is readily distinguishable from its only previously 

 described ally M. {A,) chinensis by its lower skull and much 

 smaller bulla?. IMr. Ward says that it is common at Chamu- 

 tonfT, and it was merely by an accident that he only brought 

 home the single skull now described. 



In working out this species I have had occasion to study 

 the specimens hitlierto referred by me to M. [A.) chinensis, 

 17 in numl)cr, 8 from the neighbourhood of Ta-tsicn-lu and 

 9 from Omi-san and Kiating-fu, the latter being the type 

 locality. 



The two sets agree closely with each other in all respects 

 except certain details of tooth-]iattern, in which there is such 

 an average ditference that I think the two should be distin- 

 guished subspecifically. The new form may be called 



Microtus {Anteliomys) chinensis tarquinius, subsp. n. 



M^ with only four salient angles on its inner side (in 7 out 

 of 8 specimens), chinensis having 5 (in 8 out of 9 specimens). 

 Spaces of teetii generally tending to be less frequently open 

 to each other, the two following ]5airs of spaces being taken 

 as samples: s{)ace3 2+3 of m^ closed in 5 out of 8 speci- 

 mens, open in all 9 of chinensis ; spaces 3-1-4 of m^ closed 

 in 6 out of 8, open in 7 out of 9 in chinensis. Front part of 

 »n' less like that of an Aldcola, the spaces 1+2 narrowly 

 open or closed in 6 out of 7 specimens, broadly open and 

 Alfieola-Vike in 8 out of 9 chinensis. 



Dimensions of the type : — 



Head and body 108 mm.; tail 68 ; hind foot 21 ; ear 15. 



Skull: occipito-nasal length 28*7; condylo-incisive length 

 27'5; zygomatic breadth KM; upper molar series (crowns) 6'2. 



Bab. (of type). 23 miles S.E. of Ta-tsien-lu, W. Szc- 

 chwan. Alt. 10,000'. 



Ti/pe. Adult malo. B.M. no. 11. 2. 1. 207. Original 

 number 2328. Collected 15th June, 1910, by M. P. Ander- 

 son. Presented by the Duke of Bedford. 



8. Microtus (Anieliomi/s) custos, sp. n. 



S . 2, G, 7, 11, 21 ; ? . 1, 10, 16, 17. A-tuu-tsi, N.W. 

 Yunnan. 11,500-12,500'. 



A brown vole looking like a Caryomys, but with teeth as 

 in Anteliomys. 



General appearance very much as in M. {Caryomys) nux. 



