MAMMALS FROM THE INNER HEBRIDES. 931 



It may be noted as an interesting circumstance that the neigh- 

 bouring Highland form of jS. a. castaneihs is approached in size 

 most closely by the shrew of the island most recently separated 

 from the mainland, Jura, and least by that of the longest 

 separated, Islay. This coincides with the view that smallness in 

 S. araneus is a modern character, developed in Scotland, for 

 example, since the separation of Islay from the mainland. 

 Similai'ly, light dorsal coloration might be regarded as yet more 

 modern, developed throughout Great Britain since the separation 

 of Jura. That largeness in the group is primitive is confirmed, by 

 fossil evidence, which can, however, obviously throw no light on 

 the question of ancestral colour. The view that dorsal lightness is 

 primitive in Common Shrews has been considered to be supported 

 by its universal presence in young specimens. If, however, this 

 latter view be correct, the Jura and Grigha shrews must have an 

 unusual history ; on the one hand they may be regarded as con- 

 vergent forms, strikingly parallel with Continental >iS'. a. araneus ; 

 on the other hand they must be regarded as representatives of a 

 successful modern group, which, having excluded the older light 

 group from the European mainland, has itself, in part, been 

 excluded from the British mainland. The improbability of both 

 these assumptions encourages the statement that the description 

 of the Jura and Grigha shrews tends to confirm the view that 

 dorsal lightness in S. a. castaneus is a secondary development 

 from a dorsal clove-brov/n condition ; this view is perhaps sup- 

 ported by the fact that, even in ;S'. a. castaneus, the young coat is 

 of a slightly lighter tint than is that of the average adult. 



SoREx ARANEUS ARANEUS Linmeus. 



Sorex araneus castaneus Barrett-Hamilton & Hinton, P. Z. S. 

 1913, p, 823 (1). 



Material examined and Dimensio7is. Six adults (3 d" , 3 $ ) 

 collected by Sheppard in May 1912 in Jura. Five adults 

 (2 d" , 3 $ ) and six young adults (3 c? , 3 $ ) collected by Hutchin- 

 son in June and July 1922 in Grigha, 



Jura, HB, T. HP, 



Average of six adults 72"5 3o'3 12 



GieHA. 



2. Adult (?, 30.6. 22 70 37 13 



5.' „ (?, 30.6.22 76 40 14 



6. „ 2,30.6.22 70 32 11-5 



11. „ ?, 2.7.22 71 34 12-5 



15. „ ?, 3.7,22 77 37-5 12 



1, Young adult (?, 30.6.22 62 35* 12 



10, ., „ <?, 2.7.22 63 37 13 



14, ,, „ S, 3.7.22, 66-5 34 12 



3. „ „ 9, 30.6.22 71 39-5 13 



4. ,. „ ?, 30.6.22 68-5 38 12 



7, ,, „ ?, 1.7.22 59 36 12 



Average of five adults 72'8 38"3 12"6 



The term "young adult" is applied to specimens in the light summer coat, their 

 feet being abundantly clothed with hair. 



* Tail damaged in trap. 



