NOTES ON SOME SMALLER BRITISH MAMMALIA. 301 



For comparison, I give the same of seven selected specimens 

 of Mus sylvaticus : — 



No. 



Sex. 



H. B. 



Tail. 



Hind foot. 



Ear. 



Skull length. Skull breadth . 



1 



Female ... 



88-5 



88 



23 



18 



broken 



broken 



2 



Male 



112-5 



83-5 



24 



16 



>i 



») 



8 



Male 



100 



96-5 



23-5 



13 



27 



13 



4 



Female ... 



95 



85 



23 



20 



broken 



12 



5 



Female ... 



90 



damaged 



23 



13 



24 



12 



6 



Female ... 



103 



83 



23 



13 



20-3 



13 



7 



Male 



97 



88-5 



25 



17 



broken 



broken 



From the above tables it will be seen that the Yellow-necked 

 Mouse has a longer tail than Mus sylvaticus, and this difference 

 alone would entitle it to specific rank, according to many 

 zoologists, for we see that in the case of other small mammals 

 measurements only can be relied on for discriminating the 

 species ; for instance, the immature Common Shrew and adult 

 Pigmy Shrew so closely resemble each other that they can only 

 be distinguished with satisfaction — so I am informed by Mr. 

 O. Thomas — by the measurement of the hind foot, that of the 

 Pigmy Shrew being much smaller. Again, the Skomer Vole 

 differs only from the Bank-Vole in its superior size, though it is 

 true the colour on the lower back is more grey ; but apparently 

 colour would go for nothing, as Capt. Barrett-Hamilton says, 

 writing of Mus sylvaticus ivintoni, that the yellow pectoral band 

 may or may not be present, which we ourselves would have 

 thought to be a distinguishing character, and I agree with and 

 follow Mr. de Winton in giving M. flavicollis full specific rank. 

 The most beautiful specimen of M. flavicollis I have ever seen 

 is one in my possession, taken during the winter of 1906 in 

 Gloucestershire. I append a description : — Upper parts fawn, 

 mingled with long black hairs ; a broad black dorsal line ; line 

 of demarcation clearly defined ; under parts snow-white ; a 

 small yellowish pectoral band ; under surface of tail pure white. 

 I have found both M. flavicollis and sylvaticus in moult in May. 



Bank- Vole (Evotomys glareolus). — This little animal is far 

 more aquatic in its habits than is generally supposed. I have 

 alluded to its partiality for swampy ground in a previous note 



