On some new Forms o/Ocliotoiin. 187 



X\ 111. — On sonic new I'\>vnis o/" Ocliotona. 

 By Ommmeld Thomas. 



(Published by permissiim of the Trustees of the British Museuui.) 



\Viiii.K working out tlie Pikas obtained by Dr. WoUastoti on 

 Mt. Kverest, the following new forms of the genus have been 

 noted, and may be now described. 



These animals are of uiiusii;il ditliciilty owinj^ to their 

 gr«>at and abnost contiiuioiis ehani;es ot pfhii^c, so that for a 

 satisfactory kM()\vledi;o of any species, even from a single 

 b)eality, quite a number of specimens are needed — ranging" in 

 thite at least from May to Sepfeml)er, during which period 

 most of the seasonal change takes place. Once in the winter 

 palage, no further elianoe occurs until the following May. 



Ochotona nubrwa, sp. n. 



A small species of the rot/hi group. 



General colour of the specimens available al)out as in early 

 summer specimens of 0. ro>/lei wanll, or rather paler grey. 

 Fur not very long, haiis of back in a sumuier skin about 

 12-lo mm. in length. Face, nape, and shoulders grey, with 

 a slight fidvous tinge; hind back clearer grey, the runip 

 again more drabby. No evidence that n rufous mantle is 

 uc(|uired in the late summer, as it is in roijlei. Under sui face, 

 us usual, with the hairs daik slaty at base, whitish terminally. 

 Kar-patclies dull l>utl'y whitish, not very largo or conspicuous. 

 Area below ears butFy. Ears of moderate size, blackish 

 behind, with white edges. 



Skull decidedly smaller than that of 0. Kvirci?/, and narrower 

 in pro})ortion, the breadth across the brain-case much U ss 

 than in roi/h'i ov its Kashmir representative w<ir(/i, and still 

 more so than in nuwroti^i. Palatal foramina very widely 

 expanded in their posterior half, much more so than in tiie 

 other species. Bullaj small and looking narrow, owing to 

 their being apparently more vertically placed, like a disc 

 nearly on edge. 



Dimensions of the type (measured in the flesh) : — 



Head and body 184 mm. ; hind foot ."i.i ; ear 21. 



{Skull: greatest length 42: condylo-incisive length '^^ ; 

 zygomatic breadth 11V5 ; nasals 14*3 x 4-7; interorbital brea.itb 

 4*2 ; breadth across brain-case 15'4 ; palatal foramina lO'Sx 

 4*6; palatal bridge 2*4 ; antero-posterior length of bulla 10. 



Hub. Ladak, along the Nubra Valley, down to the Pang- 

 Kong Lake. Type from Tiiggur, Nubra Valley, alt. 10,0(>0', 



