59 



TWO NEW LEGGADA MICE FROM SIAM. 

 BY C. BODEN KLOSS, F. Z. S. 



- These mice are part of a collection of mammals from Western 

 Siam made by Mr. K. G. Gairdner, about which I have written in 

 previous volumes of this Journal. 



Some years ago Mr. G. S. Miller united the genus Leggada 

 of Gray with Mus l , and Mr. Oldfield Thomas acquiesced in this 

 opinion. When I first examined Mr. Gairdner's mice it seemed 

 to me that they represented a new genus, for I was unable 

 to find one in which they could be placed: but at about the same 

 time Mr. Thomas, in England, came to the*conclusion that Leggada 

 was worthy of recognition and decided to revive it 2 . Mr. Thomas, 

 who has since then seen these specimens, writes me that they 

 belong to Leggada as he now conceives it, and has kindly sent me 

 an example ot Leggada pahari from Sikkim3 to which some of the 

 specimens are closely related. 



These animals are like Mus with notched incisors, ml longer 

 than m- and m'3 combined and with no frontal ridges ; but with- 

 out any masseteric knob at the anterior roots of the anteorbital 

 plates and the palatal foramina not narrowing to acute terminations 

 between the molars. The external appearance is apparently similar 

 but the pelage is spiny. 



The following Key indicates the differences, as far as Indochinese 

 species are concerned, between some genera of mice which have the 

 bevelled edges of the upper incisors notched. 



J . Palatal foramina penetrating deeply between the molars. 



a. Frontal lidges well marked : no masseteric knobs. Leggadilla. 



b. No frontal ridges. 



al Masseteric knobs present : molar laminae 



much distorted. ... ... ... Mus. 



bl Masseteiic knobs absent: molar laminae 



less distorted. ... ..* ... Tautatus. 



B. Palatal foramina not penetrating deeply between the 



molars : no frontal ridges nor mas.-eteric knobs. Leggada. 



1. Miller, Mammals of Western Europe, 1912, p. 863. 



2. Thomas, Journ. Bombay Nat. Hist. Soc, xxvi, 1919, pp. 417-420. 



3. Mas pahari, Thomas, op. cit. xxiv, 1916, p. 415. 



VOL. IV, NO. 2, 1920. 



