5G0 On a minute Shrew from T.ahe Baikal. 



less tlian half the length of the head and body, light brown 

 above, darker brown at the tip, white below. 



Skull very small and delicate; muzzle not specially 

 plender or drawn out. Interorhital region narrow, its sides 

 evenly converging forwards. Walls of inesopterygoid fossa 

 plightly imperfect, reticulated, though less detinitely than in 

 Blarinella. Foramina in base of skull behind entopterygoids 

 unusually large. 



Upper unicuspids evenly decreasing in size backwards to 

 the fourth, the fifth slightly larger than tlie 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. 



Skull : greatest length (bone otily) 12*5 ; condylo-incisive 

 length 12"9 ; greatest breadth 5*9 ; interorhital breadth 2"3 ; 

 ])cilatal length 5*J ; breadth between outer corners of m^ 3*3; 

 upper tooth-series 5*3 ; front of p^ to back of m^ 2*8. 



Hah. Listvineechnoya, on L. Baikal, near Irkutsk. Alt. 

 1400'. 



Tiq-^e. Old female. B.M. no. 15. 3. 9. 10. Original 

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

 Presented by Oldfield Thomas. 



" Caught ill pit-fall in forest."— (?. A. B. 



This tiny shrew, the smallest mamuial of the Palsearctic 

 region, seems only to be related to Sorex hawkeri and 

 tschersh'i. From the former it differs by its still smaller 

 size, shorter tail, shorter tooth-row, and smaller uiiicus|nds, 

 the first three of which are 1*1 mm. in length taken together 

 in haulceri, 0*8 in hnrneyi. Tlie type-skuli of S. hawheri is 

 unfortunately crushed, so that no comparison in that respect 

 is possible. 



From the IJssuri species S. hnrneyi differs by its non- 

 contrasted drabby underside as compared with the " merklich 

 abgegrenzt silbergrau-weisse Unterseite^'' of that species; 

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

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

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

 photograph published by Dr. Ognev. 



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

 the mesopterygoid lossa has been described as peculiar to 

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

 it does not occur in 8. minuius^ but is present in certain of 

 the smaller American species of the genus. 



