1881.] INDIAN SPECIES OF MUS. 543 



ears, long soft fur, white belly, and especially its loug, white-tipped, 

 hairy tail, cause it to be distinguishable at the first glance from all 

 other Indian Muridae ; and I have had great pleasure in connecting 

 with it the name of J\Ir. W. T. Blanford, to whose generosity in pre- 

 senting to the British Museum his fine series of Indian Muridce in 

 spirit, and in lending me all his Indian skins, I owe the fact of my 

 having been so far able to work out the Indian species of this most 

 difficult genus of Mammals. 



The skull of this species (Plate LI. figs. 4 & 5) is very distinct 

 from that of 21. alexandrinus. The following are the dimensions of 

 the skull of the adult male of J/, blanfordi and of that of a speci- 

 men of 21. alexandrinus var. rvfescens, which, being of precisely the 

 same length, is particularly suitable for the purpose of comparison : — 



Mns blanfordi ^J. Mus nifescens'^ ^. 



Kadapa. Calcutta. 



Total length 1-65 1-65 



Greatest breadth -8 -8 



Length of lower jaw- -96 -QG 



Nasal bones '68 '.58 



Breadth between orbits .... '28 -26 



Anterior palatine foramina . . '35 -30 



Incisors to 1st upper molars. . '44 "44 



Breadth of interparietal .... '4.5 '41 



The proportions of the two skulls would thus seem to be almost 

 exactly the same, that of 21. blanfordi having rather longer anterior 

 palatine foramina, and broader interparietal bones. The following 

 differences, however, form a ready means of distinguishing the skulls 

 of the two species : — 



In 21. ritfescens the fronto-parietal sutures form together a very 

 obtuse angle forward, sometimes almost a straight line across the 

 skull ; but in 21. blanfordi they form but httle more than a right 

 angle, the frontal extending in the middle line much further back- 

 wards between the parietals. 



The shape of the interparietal bone is very different in the two 

 skulls. In 21. rufescens it is more or less five- or six-sided, with 

 the angles well developed ; but in 21. blanfordi the bone, as may be 

 seen in the figure, has only two distinct angles, namely those at the 

 outer ends of the bone, its front and back edges being simple 

 curves. 



In the above-mentioned points the two skulls of 21. blanfordi both 

 agree perfectly ; but one of the characters mentioned in the original 

 description is now found to be a question of age. This is the shape 

 of the front edge of the anterior zygoma-root, which was said to be 

 slanting instead of perpendicular. The older skull, however, has 

 this edge quite upright, as in other Rats ; and I have therefore had 



' This term is here used instead of the more correct form Mils alexandrinus. 

 Tar. rufescens, as being more convenient for ordinary use. 

 '^ From the condyles to the most anterior point of the actual bone. 



