404 THE ZOOLOGIST. 



The bleaching of the colour of the tail takes place most 

 rapidly at its tip, gradually proceeding bodywards. Naturally 

 there is some variation between different individuals as to the 

 degree of bleaching attained at any date, so that in the winter 

 months some Squirrels may be seen with brown and others with 

 whitish tails. But as every individual passes through the same 

 series of changes, only varying the date, there is really far less 

 true variability — that is, difference between one individual and 

 another — than a casual observer would at first suppose. 



Concurrently with their bleaching the hairs wear down or fall 

 out, so that the brush gradually becomes thinner and poorer, 

 until the new one attains its full length in September. The 

 growth of the latter takes place from the body towards the tip, 

 the terminal hairs being the last of the white summer coat to be 

 superseded. 



It will be noted that the bleaching takes place mainly in the 

 winter and early spring, so that it cannot be assigned to the 

 special action of the summer sun. 



This description refers entirely to the long hairs of the tail, 

 which are the only ones that affect its general colour, and which 

 stay in place a full year before they are changed in correspondence 

 with (though rather before) the autumn moult of the body-fur. 

 Whether there is any regular growth of tail-hairs in corre- 

 spondence with the development of the summer body-coat is 

 doubtful. One skin, obtained on May 24th, seems to show that 

 some short blackish hairs appear on the tail between the long 

 ones just at the date of the spring body-moult, which hairs are 

 not to be found a little later in full summer skins, and have 

 perhaps been moulted as soon as developed. Further observa- 

 tion is needed on this point. 



II. Ear-tufts. 

 The hairs of the ear-tufts follow very much in their changes 

 those of the tail. The terminal hairs of the ear-tip, belonging, 

 like the brush-hairs, to the autumn coat, lengthen and be- 

 come noticeable in September, attaining their maximum about 

 January. Like the tail-hairs, they steadily bleach all the time 

 from their original dark brown colour, and get white, thin, 

 and poor in May and June. In most specimens they have 

 altogether disappeared by July, although in rare cases a few 



