On the Affinities of the Orhnerj Vole. 323 



Collected 1st July, 1902, and presented by C. W. Campbell, 

 Esq.,C.M.G. 



Tliis very handsome little species seems alone allied to 

 C. songorus, Pall,, and G. dichrootis, Sat., but may be readily 

 distinguished from the former by its smaller ears and rather 

 different colour, and from the latter by its more completely 

 hairy soles and its prominent dorsal line. 



XXXIX. — The Affinities of the Orkney Vole (Microtus 

 orcadensis, Millais). By C. I. FoRSYTH MAJOR. 



In a joint paper by Mr. Eagle Clarke and Professor Charnock 

 Bradley are published some new and interesting observations 

 on the Orkney vole discovered by I\Ir. Millais in the Orkneys 

 and certain parts of Shetland *. I have had an opportunity 

 to verify the accuracy of the facts communicated, but I venture 

 to take exception to the interpretation given to these facts, as 

 being intended to throw light on the affinities of the species. 

 By representing the Orkney vole as being in some respects an 

 intermediate form of the field- and the water-vole, but more 

 nearly allied to the latter, a misleading conception of its true 

 aflSnities is conveyed. 



The two British species just mentioned are so widely apart 

 from each other that they have been placed into two distinct> 

 sections (subgenera) of the genus Microtus. Now the 

 Orkney vole, by its external characters (number of foot-pads 

 on the hind sole, absence of abdominal musk-glands), as well 

 as by the character of its teeth, is clearly a member of the 

 same subgenus as the field-vole, and therefore much nearer 

 related to the latter than to the water-vole. The peculiarities 

 of its skull by no means contradict this statement. Great 

 width of the skull, relative shortness of the brain-case, and 

 elongation of the rostrum, are not peculiarities proper to 

 the water-vole alone ; they occur in other subgenera also. 

 Within the subgenus to which our common field-vole 

 (Ji. agrestis) belongs it is the M. arvalis and its allies, one 

 of the field-voles of Continental Europe and Northern Asia, 

 which the Orkney vole approaches most in the characters of 



* " On the Vole aud Shrew of the Orliney Islands," by Wm. Eagle 

 Clarke. With Koport by Prof. O. Charnock"' Bradley, M.B., CM. (Ke- 

 printcd fruni 'The Annals of Scottish Natural History,' January 1U05.) 



