












‘ENTS OF PART XVI. 
RODENTIA (Rodents)— 
Group Orcadensis— ait 

= The Orkney Grass Mouse ; : : any 
" Locally Extinct Voles_. : ; : > | 407 
Genus MWimomys ; : 5 ; ; S478 i 
Genus Arvicola : ; : : . 476 
The British Water Rat. : : : a Lys) 
The South British Water Rat. : PASE 
The Black Water Rat : : . ‘ 7 4cs 
Sub-family Murine. 3 : ; : 5 A407, 
Genus Apodenius : ; ; , : . 502 
The English local names have been revised in part by Mr W. W. Skeat, 
M.A. (assisted by the late Professor W. W. Skeat), and in part by 
Myr C. M. Drennan, M.A. Lond., late Scholar Emm. Coll. Camb. ; 
the Celtic and Gaelic names by Dr E. S. Quiggin, M.A., Ph.D., 
Fellow and Lecturer in Modern Languages and Celtic of Gonville 
and Caius College, Cambridge; while a list of Scottish Gaelic 
names has been supplied by My C. H. Alston. Much information 
has been taken from Mr G. S. Millers recently published 
| “ Catalogue of the Mammals of Western Europe,” the use of the 
: MS. and proofs of which before publication was kindly permitted 
by the Trustees of the British Museum of Natural History. 
__ ILLUSTRATIONS 
FULL-PAGE (Coloured and Black and White). 
British MWzecroteéne (Skins); (1) MWicrotus hirtus; (2) M. agrestis 
' neglectus ; (3) M. orcadensis ; (4) M. agrestis exsul. (Coloured.) 
Water Rats. Crown Views of slightly worn Cheek-Teeth of Muride. 
i 
i FIGURES IN TEXT. 
Right Cheek-Teeth of M/czcrotus orcadensts orcadensis ; Right of m, of 
M. 0. sandayensis ; posterior palate of JZ, 0. sandayensts. 
Plan of Nests of Orkney Vole. 
Fossil Right m, of IZ. anglicus and of Microtus ratticeps. 
Chionomys nivalis ; A, left m,; B, left m*; crown view. 
_~Pitymys subterraneus. Right upper and Left lower Cheek-Teeth. 
~ Cheek-Teeth of Wimomys. 
Dorsal View of Adult Skull of Avvecola amphibus. 
Spoor of Water Rat in Snow. 
Water Rat Burrows and Refuges. 



