396 JOURNAL, BOMBAY NATURAL HIST. SOCIETY, Vol. XXVI. 



The skull is characterized by its large size (condylo-basal length 

 averaging about 41 mm.), robust build and by features indicating a 

 powerful development of the temporal muscles. While the cranial 

 and occipital breadths are, in relation to the condylo-basal length, 

 about as in European rattus, the least intertemporal distance is 

 greatly diminished — being usually equal to considerably less than 30 

 per cent, of the condylo-basal length, or 70 per cent, of the cranial 

 width. The temporal lines are in contact with the interparietal, 

 so that the parietals have no intertemporal articulation with the 

 supraoccipital. The temporal wing of each parietal is large, its 

 length being equal to at least half the full length of the squamosal. 

 Minor differences in the proportions of the palate, tooth-rows and 

 bullse, will be best appreciated from the comparisons made in 

 Table II. 



Local variation : — This subspecies appears to be rather widely 

 distributed in Sikkim ; specimens were obtained by the Survey from 

 Singhik, Ringin, Rongli and Gopaldhara, as well as from Hazimara 

 (Bhutan), in addition to the type locality. The specimens 

 from each locality are usually very uniform among themselves, 

 but often they are more or less readily distinguishable from 

 those from the other localities by various peculiarities of colour and 

 pelage. The cranial characters, large size and the presence of 1 2 

 mammte in the females prove to be very constant features 

 everywhere. 



Singhik (4,600')— 



5885 2, 8 Feb. 1914 145^181—31—22 

 •145 5886 $,8 „ „ 168—188—32—24 



These have rather brightly coloured backs and pure white bellies. 

 The larger specimen shows 12 mammse; its skull (condylo-basal 

 length 39-5 ; teeth half-worn) is quite typical. 



EiNGIN (6,000') — 



•146 6222 s, 16 Jan. 1915 159— 188— 34— 23- Weight 4 oz. 



6223 2,16 „ „ 131—163—31—21 „ 2^,, 

 These are very soft furred rats, with dark backs and pure^ white 

 underparts; the feet are light with an obscure dusky stripe on 

 upper surface. The skull of the male, although small (condylo- 

 basal length 37-5 ; teeth nearly half- worn), is quite typical in form 

 and proportions. 

 Rongli (2,700')— 

 •138 5857 d , ^6 Nov. 1914 177— 230— 36— 25- Weight 6 ozs. 



5824$, 21 „ „ 155—212—32—23 „ 4^ „ 

 •140 5835$, 23 „ „ 162—203—34—23 „ 4 , 

 Average of 8 :— 150— 192— 32-7-22-6 



T)o <y 100— 128— 21-8-15-1 



