700 SCIURID^— SCIURUS 



Norway) that the Norwegian Squirrels (now referred to 6". v. vulgaris 

 and V. varius) have similar moults to those observed in leucourus. 

 Thus the body-fur is shed and renewed twice a year — in spring and in 

 autumn ; the ear-tufts and tail-hairs only once — in the course of the 

 summer. Though subject to considerable individual variation, the 

 precise moment of change, as in England, appears to depend very little 

 upon weather. At the autumn moult, the first grey hairs appear on 

 the posterior half of the back ; then they appear on the upper surface 

 of the thighs and forepart of the back ; later they spread over the 

 flanks and fore-limbs ; and lastly on the belly and inner sides of the 

 thighs. The spring moult follows a converse order : the belly first 

 becomes thin haired ; then the outer sides of the arms become red ; next 

 the flanks and inner surfaces of the thighs become yellowish-red ; after 

 this the grey hairs fall from the outer sides of the thighs, and lastly 

 from the back, where in the neighbourhood of the rump long pendulous 

 grey hairs can remain until a very advanced date. The colour-changes 

 of the Norwegian animals are produced solely by the replacement of 

 the old hairs by a new growth, and the bleaching process, so character- 

 istic of the British species, is apparently quite unrepresented in them, 

 as well as in the other continental races of 6". vulgaris. 



Bleaching is known to occur also in Heliosciurus mutabilis, a species 

 inhabiting Nyasaland (Thomas, P.Z.S., 1894, 140), and in Ratufabicolor, 

 a Giant Squirrel inhabiting Java (Bonhote, A.M.N.H., [7] v. 490). In 

 leucourus, as pointed out by Thomas, it "takes place mainly in the 

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

 action of the summer sun." Further, it affects only the annulated 

 hairs with blackish-brown pigments, and not the unannulated hairs with 

 rufous pigment ; thus in " February and March skins, the whole animal, 

 from nose to tip of tail (but not the rufous limbs), is bleached to one 

 uniform dull yellowish or drab tint" (Thomas, Zoologist, 1896, 406). 

 It seems probable from these facts that there is an important difference 

 in the chemical constitution of the red as opposed to the blackish- 

 brown pigment ; the bleaching of the latter appears to be a process 

 strictly comparable with that which we have described as taking place 

 in the hairs of the House Mouse (antea, p. 643). 



It is of interest to note in conclusion that CoUett {pp. cit., 220) has 

 described two distinct pelages of the young Norwegian Squirrels. 

 According to him, nestlings first develop a red coat in which there is 

 usually a more or less strong intermixture of whitish-grey hair, 

 especially noticeable on the head and flanks. In this pelage, especially 

 in Northern Norway (Finmarken), the grey tone may be as strongly 

 evident as in the winter coat of many adults. This " nestling " pelage 

 is changed apparently wholly or in part when the young are half grown, 

 and it is succeeded by the true juvenal pelage, which is quite red. The 



