244 THE ZOOLOGIST. 



Malay Peninsula and Borneo. This bleaching is entirely absent 

 in a large form {R. gigantea), while being present and a very 

 conspicuous feature in the very closely allied form {R. hicolor), 

 although chiefly confined to the body. 



In R. affinis (another species) it is general and uniform both 

 on the body and the limbs, and in R. ephippium is almost 

 entirely absent, or, if present, confined, as in the case of the 

 European Squirrel, to the tail only. 



To account for changes of this kind as being due merely to 

 the bleaching or wearing of the hairs seems to me hardly a 

 sufficient explanation, for if that were the sole cause there would 

 be no reason why one portion of the animal should bleach more 

 than another. It might be accounted for in some cases, as 

 Mr. Thomas has pointed out in our European Squirrel, by the 

 absence of a moult ; but such a solution would hardly hold 

 good in the case of R. hicolor, where the line of demarcation is 

 irregular, and varies in individuals ; or again, in the case of 

 R. affinis, where the bleaching, which is general, follows so 

 quickly on the growth of the new pelage that hardly any speci- 

 mens in unbleached pelage are known in our museums. 



It seems to me that the only way to account for these 

 phenomena is to suppose that these hairs must sever their 

 physiological connection with the body, and that, when dis- 

 connected, the destructive action of light and weather is able 

 to act ; but to thoroughly elucidate this matter microscopical 

 examination of fresh specimens is necessary. My object in this 

 paper is merely to draw attention to the facts. 



Apart from this seasonal change by bleaching, there are two 

 other forms of seasonal pelages to be observed. The one, which 

 may be noticed on S. herdinoni, and doubtless many other forms, 

 in which the pelage worn in summer is a much brighter and 

 more intense edition of that worn during the colder portions of 

 the year. Whether the change takes place by abrasion or by 

 moult, I am unable to say — possibly the former, as the dark 

 lateral stripes can be clearly distinguished in the winter pelage, 

 but very much concealed owing to each hair having a dark brown 

 tip. The other seasonal pelage is that in which the brightest 

 phase takes place in winter, and, instead of being a brighter 

 edition of the duller pelage, is markedly distinct. The only two 



