1907.] ON ABNORMALLY-COLOURED COMMON SQUIRRELS. 517 



an abnormal change in the colour of the fur. The Squirrels, 

 which had been reared by a domestic cat, were presented to the 

 Society by Mr. A. Heneage Cocks, F.Z.S., and had been exhibited 

 in the Gardens with their foster-parent and one of her kittens. 

 When received at the beginning of May, they were just strong 

 enough to crawl feebly and were well covered with their first coat 

 of fur, which was of the rich ruddy-brown hue characteristic of 

 the new coat in ordinary English Squirrels. A week or two later, 

 when they were sufficiently active to climb about the cage, it was 

 noticed that the fur was gradvially losing its colour and turning- 

 grey. The change was efiocted with tolerable uniformity all over 

 the head, tail, and body, with the result that by June 18th the 

 animals were of a silvery-grey tint. On the feet and along a 

 narrow strip bordering the white of the belly the red persisted 

 longest. Ultimately the feet also turned white, but on the 

 ventral area, especially on the inner side of the thigh, some red 

 hair underwent no alteration in colour. The change was accom- 

 plished without any sign of alteration in the thickness, length or 

 quality of the coat ; nor was there any other evidence of moulting. 

 In fact, careful watching of the pi'ocess left very little doubt that 

 the greyness resulted from the fading away of the red pigment in 

 the individual hairs. 



[During the three weeks that followed the exhibition of these 

 Squirrels before the Society, the fur lost a good deal of its silvery 

 lustre and became somewhat duskier, apparently from soiling ;. 

 but no further change in the colour took place except the fading 

 of the feet above alluded +-o. By the middle of July there was 

 evidence of the recovery of the colour natural to the species. 

 This showed itself first on the head and tail. The tail began to 

 look thin and meagre fi'om the dropping of the hair ; and the 

 hairs that were shed were gradually replaced b}' others of a dark- 

 brown hue, the distal darkening before the proximal portion. 

 Similarly on the head, the greyish-white hairs were moulted and 

 replaced by reddish-bi-own hairs ; but on this region the coloured 

 ai-ea, beginning on the forehead and nose, gradually spread back- 

 wards over the nape, encroaching upon the greyish- white area 

 and being marked ofi' therefrona by a sharjD line of demarcation. 

 That the greyish-white hairs did not themselves become pig- 

 mented and turn dark was shown by the circumstance that they 

 were longer than the coloured hairs. 



No explanation could be ofi'ered either for the loss of the colour 

 in the hair or for the midsummer moult of the faded hair. The 

 only abnormal feature in the history of the Squirrels was their 

 nurture on Cats' milk instead of on Squirrels' milk. There was 

 conceivably a connection between the unusual food and the con- 

 dition that caused the canescence or fading of the hair.] 



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