420 



MURID^— EVOTOMYS 



with that of E. g. britannicus. From those of E. nageri nageri and 

 E. n. norvegicus (see next page), which agree with it in size, it 

 differs in its great relative depth, in the short, broad, rather strongly 

 ridged and angled brain-case, conspicuous mastoid region, and un- 

 usually elongate, centrally contracted almost spatulate nasals, which 

 are decidedly longer than the diastema. The post-orbital processes of 

 the squamosals are small, but unusually well defined, and send well- 

 developed ridges backwards and upwards nearly to the anterior edges 

 of the parietals. 



The cheek-teeth are large, and similar to those of nageri, ni^ having 

 normally three infolds on the inner side (Fig. 63). 



DIMENSIONS IN MILLIMETRES: — 



Skull: — Condylo-basal length, 24-8 to 25-8; breadth at zygomata 

 14-2 to 15 ; at inter-orbital constriction, 4 to 4-2 ; at occiput, 12 to 12-6; 

 median occipital depth, 6-4 to 7-0 ; greatest length of nasals, 'j-6 to 

 8-2; of diastema, 6-8 to 7-2; of mandible, 15-6 to 16-4; of maxillary tooth- 

 row, 5-6 to 6 ; of mandibular tooth-row, 5-4 to 5-8. 



History: — Specimens of this mouse were taken by Drane at 

 Skomer Island in June 1897. He saw at once that his captures 

 differed from glareolus, being much larger and having distinct teeth 

 (" A Pilgrimage to Golgotha," in Rep. and Trans. Cardiff Nat. Soc, 

 xxxi., 1898-99,46, 1900). In an account read isth Dec. 1898 (Trans, 

 cit., xxxiii., 1 900- 1 90 1, published 1902), of a second visit to Skomer 

 Island in June 1898, Drane added that he felt inclined to regard his mice 

 as representing " a hitherto unnoticed variety." He took every trouble 

 to get his specimens correctly named, and for that purpose he submitted 

 them, both living and dead, to the Linnean Society of London {Proc, 

 June 1899,63), and to the authorities of the British Museum; but so 

 great was the lack of knowledge at that date that he received no more 

 satisfactory answer than vague suggestions about a " local variety of 

 s:lareolus" 



