[ ^15 ] 



VIII. 



AN ADDITION TO THE LIST OF BRITISH BOREAL' 



MAMMALS. 



By CAPTAIN G. E. H. BARRETT-HAMILTON, B.A., 

 F.Z.S., M.R.I.A. 



Eead May 11, 1903. 



In the present Paper I wish to describe a remarkable Bank Vole 

 or Red-backed Mouse {Evotomys) inhabiting the small island of 

 Skomer, off the coast of Pembrokeshire, "Wales. 



Skomer Island^ is said to owe its Danish name, which, according 

 to some writers, signifies " the rocky," to its rough character. It 

 is the haunt of immense numbers of Puffins, Fratercula arctica, and 

 of Manx Shearwaters, Puffinus anglorum. It has an area of about 700 

 acres, and, forming the southern horn of the crescent of St. Bride's 

 Bay, is parted from the mainland by a narrow sound some two miles 

 wide. There is but one house upon the island ; in connexion with 

 this there are about 250 acres of cultivation. The island is without 

 bush or tree, and is said to be very wind-swept. 



I first heard rumours of the existence of a peculiar Vole on Skomer 

 Island in or about the year 1898. In October of that year Mr. H. W. 

 Marsden, of Clifton, was so kind as to send me a pair. They had 

 been caught by Dr. Y. H. Mills, of Haverford-West. Dr. Mills has 

 since obtained for me several excellent specimens, so that I now 

 possess a dozen in all. 



I believe, however, that Mr. R. Drane, of Cardiff, deserves the 

 credit of having been the first to collect and recognise the interesting 

 character of the Skomer Voles. Mr. Drane sent specimens for exhibi- 

 tion to the Linnean Society of London, but they were regarded by the 

 members present as "the Common Bank Vole, Microtus glarcolus.^''^ 

 Mr. Drane' s own opinion, however, as expressed to me in a letter, is 

 both different and decided. He wrote : " They are, I contend, a local 



^ These details are taken mainly from the Rev. Miu-ray A. Mathew's '' The 

 Birds of Pembrokeshire and its Islands," 1894, pp. xxx to xxxi. 



*Proc. Lion. Soe. Lond., June, 1899, p. 63. 



^ I use the term throughout in the sense given to it in the works of American 

 writers on geographical distribution. 



