204 JOURNAL, BOMBAY NATURAL HLST. SOCIETY, Vol. XXT. 



rounded, their front surface unusually roughened, their cutting edge 

 slightly notched. Lower incisors very long, projecting more out of 

 the bone than in any of the allied genera. Upper molars with the 

 relative proportions of those of Rctttus, and their structure on the 

 whole more as in the Rats than in the Mus-Leggadilla series of 

 genera. But the outer cusp of the anterior lamina of m^ (t 3 of 

 Miller) is completely absent, while there is a continuity between 

 the two inner cusps (t 1 and 4), with the second and third median 

 cusps (t 5 and 8) which appears to have developed earlier than the 

 state of wear of the teeth would lead us to expect. In the second 

 molar, the antero-internal cusp (t 1) is further back than usual, its 

 front edge behind the level of the main median cusp (t 5) with 

 which it is already in direct continuity by wear ; the inner walls 

 of this t 1 and the cusp behind it (t 4) very high and sharp edged. 

 M'' apparently of normal structure. 



DiOMYS CRUMPI, sp. n. 



Skull and teeth as above described. 



Dim-ensions of tyj^e. — Gnathion to back of interparietal, 32*5 ; 

 tip of nasals to back of interparietal, 31'3 ; front of incisors to 

 basilar suture, 25-6 ; zygomatic breadth, 16-2; nasals, 11-8x3; 

 interorbital breadth, 4-7 ; breadth between ridges on brain case, 

 12 ; zygomatic plate, 4 ; palatilar length, 16*5 ; palatal foramina, 

 8*5 X 2-5 ; anterior width of posterior nares, 2-2 ; upper molar 

 series, 5-4 ; length of m' 2-6. 



Habitat. — Pareshnath, Hazaribagh, Behar. 



Type.— SknW only. B. M. No. 15.4.3.164. Collected by C. A. 

 Crump. Presented to the National Museum b}^ the Bombay Natu- 

 ral History Society. 



Named in honour of Mr. C. A. Crump, its discoverer, whose 

 effective collecting work in various localities has so greatly assisted 

 the Survey. 



The true affinities of this animal are b}^ no means easy to 

 determine. While the general look of the skull, its slender build, 

 long narrow muzzle and notched incisor- tips suggest the Mus- 

 Leggadilla series of Muridoi, its molars, both in structure and pro- 

 portions, and its well open posterior nares, are more as in Eattus, 

 although no species of that genus can be found with teeth of abso- 

 lutely similar structure. Perhaps Ilattus herdniorei and manipula^, 

 with their forwardly directed incisors, may represent a commence- 

 ment of an approach towards it, but the approach is certainly not 

 near enough to give rise to any doubt as to the generic distinction of 

 the new form. 



I trust it may not be long before specimens showing the 

 external characters of this interesting animal may be obtained, 

 while further skulls, of various ages, will help to illustrate the 



