436 MURID^— AGRESTIS 



only be distinguished by a peculiarity of the enamel-pattern, occurring 

 as a normal feature, instead of, as in other members of the group, as a 

 rather rare anomaly. If, however, a Scottish origin for the Skandinavian 

 Microtus agrestis be accepted, the sub-species exsul'xs then geographically 

 the more primitive, and it is quite natural to find the newer forms 

 exhibiting a simpler and less primitive dentition. It is also natural to 

 find exsul more closely related to the true agrestis of Skandinavia 

 than are either macgillivraii or neglectus. None of these large forms 

 are especially closely related to hirtus of England. 



The habits are not known to differ from those of other Grass Mice. 

 In Arran Mr R. W. Sheppard found the mice living mostly in scattered 

 colonies on the edges of sheltered woods and young plantations of 

 conifers on the north side of Brodick Bay ; he met with no trace of 

 them in the country around Blackwater foot. In Jura they frequented 

 open pastures and had also runs through clumps of coarse grass at 

 the edges of woods. In Mull they had scattered colonies on the cliffs 

 above Tobermory on the western sides, at Croggan in open glades on 

 hill-sides in natural woods, and on a hill at Buncosan, but were very 

 scarce in all three localities. 



In North and South Uist they are extremely abundant all over the 

 hills, and in the sandy meadows or machars ; in some localities they 

 make a network of runs in the grass. Mr N. B. Kinnear has supplied 

 sketches (Fig. 68) of the sleeping-places as found in small mounds in 

 North Uist. These blind, somewhat circular, terminals to the burrows 

 were always of the same shape and had their sides smooth, as if much 

 used ; they contained no grass or moss. 



They seem to perform a seasonal migration, being most abundant 

 in autumn on the lower grounds and near farms, while in summer they 

 are distributed all over the uninhabited districts. 



In North Uist Mr J. G. Millais has seen the collie dogs hunting them 

 all day long, when not actually engaged in work, and a collie once 

 stuffed himself so full of them that he was sick.^ 



They are hardy and do not hibernate [I have seen Skandinavian 

 specimens of agrestis taken in a forest with 2 feet of snow on the ground]. 



The habits of the Norwegian form are given with much interesting 

 detail by Robert Collett, but cannot be quoted here. It is evident that 

 in northern countries of heavy snowfall, the habits are quite distinct 

 in many respects from those prevalent in more southern districts. 

 Nowhere, however, is there any hibernation, the mice being, like 

 lemmings, active under the snow in winter. 



' See p. 432 supra. Cocks (in Norway) had a setter very nearly die from bolting 

 lemmings wholesale. 



