COLOUR VHASES OF THE RUFOUS JWRSESROE-BATS. i'71 



(5) Not all individuals pass through the whole scale of colour 

 changes. A not inconsidi'rable number would seem to remain in 

 the auburn stage; such individuals have been obtained not only in 

 October and November (when we should naturally expect them), 

 but also in January and April, together with specimens showing 

 the extreme of the orange phase. Others show an even more limit- 

 ed " colour plasticity," the colour of the upperside changing only 

 into sepia or bister, with or without a distinct yellowish " wash," 

 the uuderparts into drab-g•re3^ Such individuals are represented 

 in the material from January, April, and May (moulting). 



(G) The claws (feet and pollex) change colour together with 

 the fur turning from transparent horn brown to deep blood red. 

 The degree of coloiir change of the claws seems to be directly propor- 

 tional to the degree of colour change of the fur ; i.e., the dark 

 brown phase shows no colour change in the claws, this begins only 

 with the auburn stage, and reaches its maximum (both in the inten- 

 sity of the tinge and in the area of the claws afiected by the change) 

 of the bright orange phases. The red colour invariably shows 

 first at the tip of the claw, spreading toward its base. 



(7) The change of colour of the fur is due to a change of colour 

 in the pigment (from olive to orange), probably owing to oxidation. 

 The fact that Bome individuals exhibit no colour phases at all, 

 while others remain in an intermediate phase, may be due to 

 absence of the oxidizing element or to some factor which wholly 

 or partly neutralizes this element. 



Explanation of plates. 



By the " four colour process " employed it has only been possible 

 to give an approximately correct idea of the true colours of the spe- 

 cimens figured. 



All figures are about 3/5 natural size. 



Fig. 1. $ ad., 18 October 1912, Seriugapatam, S. Mysore, G.C.S. 

 1935, age, three and half years. Autumn moult beginning. The 

 fur on the back of the neck and shoulder is purposel}'' disarranged, 

 to show the new dark coat coming up underneath (it looks in the 

 figure, and, on hurried inspection, in the specimen as well, as if the 

 orange hairs had dark bases ; this is not the case ; the orange fur 

 is always uniform to its extreme base, or if anything lighter at base ; 

 what looks like dark bases is, of course, the new dark coat). The 

 oi'ange fur, being old and worn, has lost some of its brillianc}^ 

 Back between Sanford's brown and orange-rufous (II, 11, j), under- 

 parts nearly ochraceous-orange (XV, 15'j with the new mouse-grey 

 coat beginning to appear on throat, flanks, and anal region. 



Fig. 2. — Same sex, date, place, and age as foregoing, G. C. S. 

 1938. Autumn moult well advanced. Old orange fur chiefly 



