520 MURIDAZ:—APODEMUS 
species, distinctly greater zygomatic, inter-orbital, and cranial breadths, 
a deeper brain-case, shorter post-molar region (the bulla being, however, 
enlarged rather than diminished), longer and rather wider nasals, 
greater palatal length, slightly longer and much wider incisive foramina, 
narrower rostrum, and longer molars. 
For external and cranial dimensions, see tables at pp. 516 
and 518 respectively. 
Status :—A. s. dudez is quite clearly differentiated from the English 
A. s. sylvaticus, and may be regarded as an insular development of either 
the same stock, or else of an older stock of mice of the sy/vaticus type. 
Its exact significance cannot be appreciated until the relationship of the 
Highland Field Mice to those of England and the lowlands has been 
determined. The Field Mice of Skye and the Highlands approach 
A. s, butet more or less closely in some respects, and thus appear to 
occupy an intermediate position between it and the English sy/vaticus. 
Among other Hebridean Field Mice the Bute form is readily dis- 
tinguishable by its small size, dark coloration, and skull characters. 
The habits of the Field Mouse are not far removed from 
being typical of those of mice generally. It is a hardy, active, 
non-hibernating animal of primarily vegetarian, but, when 
necessity arises, omnivorous diet, a fine jumper, a good climber, 
a capable digger, and a fair swimmer. It may, therefore, be 
found in any situation frequented by mice, as it is not tied 
down to the habitats of those which have become specialised 
in any particular direction. Thus it cannot compete with the 
House Mouse in the dwellings of mankind, and does not usually 
accompany it or the Harvest Mouse to the stackyards. Its 
activity and preference for a diet of berries and grain rather 
than of grass, raises it above the monotony of a Grass Mouse's 
existence, and keeps it in woods and the hedgerows of 
cultivated lands; it sometimes swarms in cornfields towards 
harvest-time. But it is found also in more open and barren 
districts, and is often numerous and well grown on desolate 
islands or rough mountains. In Clare Island, Co. Mayo, 
Ireland, it inhabits the walls of loose stones right up to the 
summits of the hills, and in the opposite direction, it may be 
found on the sea beach,’ generally in the marram-grass,’ the 
1G. T. Rope, Zoologist, 1874, 3865. 
2 G. T. Rope (Zoologist, 1887, 206) thus encountered it between Dunwich and 
Sizewell, Suffolk, on a beach cut off from cultivated land by wide marshes. 
