British Forms of S.\)oAi^m\\?,. 127 



liairs which show tliroui^h here and there. An evident 

 tliun;;h not very hriglit ])cctoral spot is present, togctlier 

 witli sunie trace of a j^encral yellowish wash. 



The skull is distinctly larf^er and more massive than that 

 of hebridensis, irom which it is further distinguished by its 

 relatively less expanded zygomata, narrower interorbital 

 region and brain-ease, and greater palatal length. The 

 shoulders of the brain-case are rather strongly ridged in a 

 manner recalling A. jluvicoUis ; from the latter it is readily 

 distinguished by its much smaller bullve, greater palatal 

 length, and relatively much longer incisive foramina. 



This form is named in honour of the late Major Barrett- 

 Hamilton, to whom we owe the first scientific attempt to 

 unravel the complex histoiy of the sylvaticus group. 



Apodemus hebridensis, suhsp. ? 



Hah. EiGG. 



Material examined and dimensions. Two, collected by 

 Mr. P. D. Montague : — 



Tail, Hind foot, 

 Head without witlioiit 

 & body, hairs. claws. Ear. C.-b. 1. 

 No. 51, c?,29lh March, 191.3.... 8-"/ 78 2.3 15 23-3 



No. 56, $ , „ „ ...... 90 78 23 15 22-8 



Like the vole of the island these mice have unusually 

 long thick fur. The back is dark, the line of demarcation 

 is not sharply defined; the ventral surface has a pectoral 

 spot and median abdominal wash of buff, wdiich are better 

 devoloi)cd in the male. 



The relative dimensions of the skulls show some consider- 

 able differences from tho.se of h. hebridensis , e. y., greater 

 palatal length, wdder masseteric plate, and longer molars. 

 The teeth, however, are only slightly worn, and these diffe- 

 rences may be due to immaturity. The status of this animal 

 cannot be determined without further material. 



The wood-mice of Great Cumhrae, Gigha, Tiree, ^NIull, 

 Jura, and Islay are, in my opinion, local races of A. hebri- 

 densis^ and they fall into two groups. In the first three 

 islands their backs appear rufous, the black hairs being 

 comparatively few ; in the remaining islands a greater 

 abundance of black hairs darkens the backs. The most 

 rufous mice are those of Great Cumbrae, the darkest those 

 of Jura. 



