2 46 BRITISH MAMMALS 



entirely confined to the isolated island of St. Kilda, to which 

 it is supposed to be indigenous, and a relic of the time when 

 St. Kilda was connected with the mainland of Scotland. 



5, Mus sylvaticus wintoni. This is the mouse described by- 

 Mr. W. E. de Winton in 1894 as Mus flavkollis, a sub-species 

 (which is really the typical form of Mus sylvaticus) found 

 in Scandinavia. This is a large wood mouse, about 4^ in. in 

 length from the snout to the base of the tail, and very brightly 

 coloured. It has a long tail, which contains thirty vertebras, as 

 against twenty-seven in most of the other wood mice. Above 

 it is a golden-brown, and below pure white. The brown spot 

 found on the throats of so many of these wood mice is in this 

 sub-species extended into a form like a cross, which forms a 

 continuous band across the chest with the golden-brown of the 

 back and sides, and a cross is formed by the upward and down- 

 ward extension of this brown colour along the breast bone. This 

 mouse was discovered by Mr. W. E. de Winton in Hereford- 

 shire, but it is also found (not very commonly) in South-east, 

 East, and North-east England. It reappears again on the 

 Continent in Central and Eastern Germany and Hungary, 

 gradually merging as it proceeds eastwards into the handsomest 

 form of all the wood mice, Mus sylvaticus princeps^ which is 

 found in Rumania, and which is really (for a mouse) a very 

 beautiful little animal. 



As regards the general distribution of Mus sylvaticus in all 

 its forms, it may be described as fairly universal over North, 

 Temperate, and Central Asia, the whole of Europe except the 

 extreme north, Palestine, and North Africa. It is not found 

 in Japan. 



The wood mouse is perhaps the most prolific of all Rodents 

 whose habits have been studied. Females will breed from the 

 age of five months. They probably commence to breed about 

 the beginning of March. If the food supply is good, a female 

 wood mouse will have two litters in thirty days, the period of 

 gestation being only three weeks. Experiments which were 

 made and recorded by Mr. R. M. Harrington in 1881 showed 



