270 JOURNAL, BOMBAY NATURAL HIST. SOCIETY, Vol. XXV. 



consists of minute granules arranged in longitudinal rows so as to 

 produce a striated appearance of the hair (magnification, 710 dia- 

 meters). In the newly moulted, mouse-coloured fur (dorsal region, 

 specimen No. 1955) the colour of the pigment is some tinge of 

 olive; in the bright phase (dorsal region, specimen No. 520) this 

 colo^tr of the pigment has chancjecl to orange. How this change is 

 eflfected is, of course, a question for the bio-chemist, but it appears 

 probable that it is due to oxidation. If this is so, one may perhaps 

 hazard the hypothesis that in individuals which show no colour 

 change of this kind, or which stop short at an intermediate (auburn) 

 phase, the oxidizing element may either be entirely absent or wholly 

 or partly cou^nteracted by some other factors. 



Summary. 



(1) The coat of the young i^/imoZopA.?(s (any species) is darker 

 (duller, more matt) than that of the adult. I have seen very few 

 immature individuals of Bh. rouxi, but those examined are of this 

 dark and dull tinge. An immature individual in the bright 

 (auburn, orange) phase I have never seen in any species of Txhino- 

 lophus or Hipposideros ; it is improbable that the coat of the imma- 

 ture ever shows such colour. 



(2) Rh. rouxi moults twice a year. In South Mysore and 

 North Kanara the " spring " moult takes place in Ma}^, the 

 " autumn " moult in October. Whether there is any considerable 

 variation in the time (month) of the two annual changes of coat, 

 either among individuals inhabiting the same geographical area, or 

 between individuals from widely separated areas of India, are ques- 

 tions not answered hy my material. The autumn moult is certain- 

 ly complete {i e., affects the whole of the pelage). The same is 

 probably the case with the spring moult, but the material available 

 is very small (two examples only). 



(3) The fresh fur, both in spring and autumn, is mouse-brown 

 above, mouse-grey beneath. 



C4) In a large number of individuals this colour of the new, 

 full grown coat changes (probably rather rapidly) into much 

 brighter tinges, the upperside through auburn and Sanford's brown 

 to orange-rufous or even xanthine-orange, the underparts through 

 ochraceous-tawny to ochraceous-orange or even yellow ochre. This 

 explains the enormous " individual variation " in colour in this 

 species (as it no doubt explains similar or corresponding colour 

 variations in other bats). In autumn the colour change takes place 

 immediately after the moult, in October and November ; the exact 

 time when it occurs in the spring coat is not shown by Tnj material 

 but it will proliably be found to be in May and June. Every hair 

 of the coat, and the whole of every hair, from tip to base, is affected 

 by the colour change. 



