460 Letters, Announcements, ^c. 



old lady in this town, and was, as I am informed, originally 

 white, but latterly became, at each succeeding moult (I can 

 vouch for two myself), darker and darker (when it finally died 

 of old age, it looked as if it had been drawn down a very dirty 

 chimney) ; three Larks, Megalophonus cinereus, of a dark cream- 

 coloured white, the heads and shoulder-patches still red, but 

 much paled ; a Pycnonotus capensis, changed to a smoky-white, 

 the wing- and tail-quills being lightest; a Crithagra sulphu- 

 rata, nearly all bright yellow ; a female Chalcites klaasi, which 

 is a most interesting example, all the brown bars being changed 

 to white, the brilliant green bars remaining; two specimens of 

 Aptenodytes chrysocome, white, more or less marked with black, 

 but with the bright yellow crests unchanged ; a Sphenisci/s 

 demersus (the only one I ever saw thus) having the normal 

 black markings, but the blue back changed to white, finely and 

 sparingly mottled with black; finally, two examples of P7'o- 

 cellaria gigantea, of the permanent race which occurs to the 

 north-west, as I have before noted (B. S, Afr. p. 360), extend- 

 ing occasionally to Australia according to Dr. Bennett"^ — these 

 have a few sooty feathers occurring here and there. 



Now what I deduce from these observations (and I could 

 name many more) is, that in whatever manner the change 

 is brought about (and I believe it to be caused by weak- 

 ness), the general rule is : — that black or dark blue changes to 

 white, and white to black ; green to yellow, and red to light 

 brown ; reddish-brown to cream-colour, and blackish-brown to 

 very pale brown. Exceptions, of course, will be found ; but I 

 look upon "albinismus," " melanismus," and " erythrismus " 

 as one and the same thing, and we ought to have a compre- 

 hensive name for it. 



I have never sought for instances of albinism for this Mu- 

 seum^ and indeed have rejected many specimens of it; but 

 here are no less than seventeen enumerated ; and if this were not 

 a purely ornithological journal, I could mention nearly as many 

 similar cases from the class Mammalia. 



I am, &c., 



E. L. Layard. 



* iQu. ' Gatlierings of a Naturalist,' pp. 76, 77? — Ed.] 



