5C0 On a minute SJircw from Lidi' Baikal. 



less than linlf tlie length of the liead and body, light brown 

 above, darker brown at the tip, white below. 



Skull very small and delicate; muzzle not specially 

 plender or drawn ont. Intororliital region narrow, its sides 

 evenlv converging forwards. Walls of niesopterygoid fossa 

 plightly imperfect, reticulated, thoui^h less definitely than in 

 Bhirinella. Foramina in base of skull behind entopterygoids 

 unusually large. 



Upper unicuspids evenly decreasing in size backwards to 

 the fourth, the tifth slightly larger than tiie latter; all visible 

 from without. 



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



Head and body 50 mm.; tail 23*5 ; hind foot (s. u.) 8. 



ISkull : greatest length (bone otdy) 12*5 ; condylo-incisive 

 length 12"9 ; greatest breadth 5'9 ; interorbital breadth 2*3 ; 

 ])alatal length 5'] ; breadth between outer corners of m^ 3'3 ; 

 uj)per tooth-series 5"3 ; front of ;»* to back of vv^ 2*8. 



Ilah. Listvineechnoy.M, on L. Baikal, near Irkutsk. Alt. 

 1400'. 



Tqpe. Old female. B.M. no. 15. 3. 9. 10. Original 

 number 38. Collected 21st July, 1914, by G. A. Burney. 

 Presented by Oldtield Thomas. 



" Caught in pit-fall in forest." — G. A. B. 



This tiny shrew, the smallest mammal of the Palsearctic 

 region, seems only to be related to Sorex hawkeri and 

 ischerskii. From the former it differs by its still smaller 

 size, shorter tail, shorter tooth-row, and smaller uiiicus()id8, 

 the first three of which are I'l mm. in length taken together 

 in haukeri, 0"8 in hurneyi. The type-skull of S. hawkeri is 

 unfortunately crushed, so that no comparison in that respect 

 is possible. 



From the U>'suri species S. hurneyi differs by its non- 

 contrasted diabby underside as compared with the " merklich 

 abgegrcnzt silbergrau-weisse Unterseite'^ of that species ; 

 by its shorter skull, 12"5 instead of 13*4 mm. in length, and 

 by its markedly narrower interorbital region, 2'3 instead of 

 3'0 mm. in breadth, a difference fully borne out by the skull- 

 jdiotograph published by Dr. Ognev. 



It is curious that just after the reticulation of the walls of 

 the mesopterygoid tossa has been described as peculiar to 

 Blarinella, it should turn up again in this pigmy shrew ; 

 it does not occur in S. minutus, but is present in certain of 

 the smaller American species of the genus. 



