552 MR. o. THOMAS ON THE [May 3, 



crowded together iu the front part of the sole. The extreme of this 

 suppression is represented by the (/ominon Jerboa (Dijnis jaculus), 

 which has only one hind foot-pad ; Gerbillus has four, all close 

 together at the roots of the toes ; and Zapus (the North- American 

 " Jumping-Mouse '') has five. The members of these genera are 

 all well known constantly to rest on the front part of the hind foot, 

 and not to be in any way plantigrade, as are the Muridae with six 

 well-developed hind foot-pads ; we are therefore, I think, justified 

 in considering the Metad as showing the commencement of a 

 similar differentiation, which, however, has not gone nearly so far 

 as in the others. Mus blanfordi has its foot-pads rather crowded 

 together in the front of the foot ; so that it is possibly also rather 

 'ess plantigrade than usual. 



As to the affinities of this animal (which seems to be somewhat 

 isolated from the other Indian species), it may be seen by the 

 synopsis on p. 531, that the only character, apart from size, by 

 which to separate the Rats from the Mice is the very different shape 

 of the sixth hind foot-pad ; nnd therefore the rudiment of this pad, 

 mentioned above as occurring in one of our specimens, will be of 

 service to us. This rudiment is very nearly circular ; and there- 

 fore, as far as we can rely on any one character, even though nearly 

 universal in its application, we may, for the present, consider Mus 

 mettada a large Mouse rather than a small Rat. 



Subgenus Leggada. 



Leggada, Gray, Charlesw. Mag. N. H. i. p. 586 (1837). 



Nannomys, Peters, Monatsb. Acad. Berl. p. 480 (1876). 



First upper molars with an extra cusp on their front edge (see 

 Plate LI. figs. 10, 1 1). Fur more or less spiny. 



Hab. India and Africa. 



This subgenus was founded by Gray on his Leggada budvga, and 

 was also stated to include Bennett's Mus 2Jlafgf/irij. It has hitherto 

 been considered to be confined to India ; but Dr. Peters's careful 

 description of his subgenus Nannomys shows most conclusively that 

 it is identical with Leggada ; in fact, his characters are the very same 

 as Dr. Gray's, except that he lays rather more stress on the pre- 

 sence of spines in the fur. 



The types of Mus minutoides, Smith', from South Africa, pre- 

 served in the British Museum, certainly belong to this subgenus; 

 and so, with Dr. Peters's two species, M. minimus'- from Mozam- 

 bique, and M. setidosus^ from the Cameroons, we have three spe- 

 cies of Leggada recorded from Africa ; and there is no doubt that 

 more still remain to be described when that continent is further 

 explored. Some of the African species already described will pro- 

 bably also turn out to be members of this subgenus. 



The presence of this form in Africa was quite to be expected, 



1 S. AtV. Quart. Journ. ii. p. 157 (1835). 

 - Keise nach Mossambique, p. loo (1852). 

 '' Monatsb. Ak. Berl. 1876, p. 480. 



