On new Rhipidomys &e. from S.E. Jujuy. 183 
other subspecies. Rufous of face rather brighter than in 
rufigenis. Postauricular patch not large or very conspicuous, 
its hairs white, with their ends buffy, more broadly buffy 
than in rufigenis. Thighs more strongly suffused with dull 
buffy, which makes a more abrupt contrast with the grizzled 
greyish of the hinder back than is the case in rufigenis, where 
the brownish of the back passes gradually into the dull 
rufous of the thighs. Throat whitish, with a slight reddish 
tinge, less marked than in rufigenis. Bellythairs broadly 
slaty, with whitish tips to the hairs. 
Skull as in rufigenrs. 
Dimensions of the type :— 
Head and body 168 mm.; tail 148; hind foot 47; 
ear 22. 
Skull: greatest length 55; condylo-incisive length 48; 
nasals 18°2; tooth-row exclusive of p* 10. 
fab. Middle Mekong. ‘Type from Ban Hoi Mak, near 
Pak-hin-bun, on the French side of the Mekong, about 
Li? 50° WN. 
Type. Old female. B.M. no. 20.12.10. 2. Original 
number 7230. Collected 29th February 1920. Presented to 
the National Museum by Herbert C. Robinson and C. Boden 
Kloss. Two specimens. 
Readily distinguishable by its pale and comparatively 
coarsely speckled back from any of tlhe races hitherto 
described. D.r. fuscus, its near neighbour in Annam, is a 
dark-coloured form with conspicuous white postauricular 
patches. 
In my ‘ Lectotypes of Indian Mammals’ Dremomys rufi- 
genis should have appeared, as it was founded on five cotypes ; 
but it wasoverlooked. I now formally name no. 91. 10.7. 81, 
which was the specimen figured by Blanford, as the lectotype. 
XX.—WNew Rhipidomys, Akodon, Ctenomys, and Marmosa 
from the Sierra Santa Barbara, S.E. Jujuy. By OLDFIELD 
THOMAS. 
(Published by permission of the Trustees of the British Museum.) 
Sr. Buprn has sent home a number of admirably prepared 
small mammals obtained by him in the Sierra Santa Barbara, 
S.E. Jujuy, and among these occur the following new 
forms :— 
Rhipidomys austrinus, sp. n. 
A large species allied to R. lewcodactylus. 
