B. -Hamilton — Addition to List of British Boreal Animak. -'517 



usually with a very perceptible yellowish wash. The line of demar- 

 cation between the colours of the upper and under sui'faces moderately 

 defined. Ears nearly naked externally ; internally covered with light 

 " cinnamon-rufous " hairs. 



The rump of the only winter specimen before me shows a much 

 larger area' of brown than is present in any of the other specimens 

 (all taken in April and May). This may be an indication of a sea- 

 sonal change. 



Type of Species. — A male, registered No. 3. 7. 4. 3. of British 

 Museum Collection, presented by Dr. Y. H. Mills, Skomer Island, 

 April 7th, 1900. 



Dimensions in Millimetres. 





Head 



and 



body. 



Tail. 



Hindfoot. 



Ear. 



Maximum of 7 males and 5 females, 



114 



61 



19 



15 



Mean ,, ,, about 



110 



55-5 



18 



13-5 



Minimum, 



105 



50 



17 



12 



No accurate naturalist could possibly confound the Skomer Vole 

 with the ordinary Bank Yole of Great Britain. The greyish sides, 

 brown rump, far larger size, general proportions, and cranial characters 

 of £, s]comere7isis are such as to mark it as belonging to quite a distinct 

 division of the genus from that containing E. glareolus hritannicus, 

 Miller, the ordinary British Bank Vole. The following dimensions 

 of a number of the latter form will illustrate my meaning : — 

















Greatest 







Head 









Greatest 



breadth 







and 



Tail. 



Hindfoot. 



Ear. 



length 



of skull 







body. 









of skull. 



at 

 zygomata. 





/ No. of specimens, 



29 



36 



36 



11 



27 



21 



00 



1 



mm. 



mm. 



mm. 



mm. 



mm. 



mm. 





I Maximum, 



104 



55 



18 



12 



25 



14 



S 



^Mean, 



93 



43 



16-25 



11 



23-5 



12-75 





,' No. of specimens, 



38 



38 



36 



12 



33 



25 



t^ 



i 



mm. 



mm. 



mm. 



mm. 



mm. 



mm. 



< 



< Maximum, 



117 



51 



18 



13 



24-75 



13.5 



Pm 



^^ Mean, 



91-5 



42 



16-5 



11-5 



23-25 



12-25 



