140 ANNALS OF SCOTTISH NATURAL HISTORY 



places. I saw one last December that, at a distance, 

 appeared to have the body black and the tail white. It 

 disappeared in the branches, but I thought if I could get 

 its skin and mark it "Utah" or "Colorado" it would (?) 

 stand for a new species. Though the squirrel varies greatly 

 in colour in this part of the country, it varies very little in 

 size. Nor is there any real difference in size between the 

 male and female, as I have proved by measuring many 

 adult skulls and limb bones. The BLACK RAT (Mtis 

 rattus] is believed to be extinct. The GRAY or BROWN 

 RAT (Mus decumanus) is a pest nearly everywhere. The 

 HOUSE MOUSE (Mus musculus] abounds in all parts of the 

 country. It varies greatly in colour, being sometimes as 

 dark below as above. The FIELD MOUSE (Mus sylvaticus) 

 is common everywhere in woods and fields. It varies a 

 good deal in size and colour. Full-grown ones here gener- 

 ally range between 4 and 4^ inches in length of the head 

 and body. I think they change colour sometimes with the 

 season, as a large race here has generally yellow or brown 

 about the neck in summer ; while some of the same race 

 have all the neck and belly pure white, without a trace of 

 yellow or brown, during December and January. If this 

 race represents the English Mus flavicollis in summer, it 

 must sometimes become Mus albicollis in winter. I have 

 no more faith in Mus flavicollis and Mus hirtenses as 

 species, than I have in the black -bellied Water Shrew or 

 brown-bellied House Mouse. Age and season has often to 

 do with changes of colour. If such changes are not the 

 " outcome " of a season, they may easily be the " outcome " 

 of a century. The Harvest Mouse (Mus ininutus] is, I 

 think, unknown in this part of Scotland. The late Rev. 

 Dr. Gordon never found a trace of it after a search of more 

 than seventy years. 



The WATER VOLE (Microtus amphibius) is very abundant 

 on the banks of most of our streams. All the young ones 

 I have seen are black, and many remain black throughout 

 life, but old ones are often brown, and sometimes piebald. The 

 FIELD VOLE {Microtus agrestes} is abundant in most localities, 

 but has never been a plague in Elginshire in my time. The 

 BANK VOLE (Microtus glareolus] is also abundant here. It 



