AVIFAUNA OF LATSAN, ETC. 



291 



91. DIOMEDEA IMMUTABILIS, Mothsch. (antea, p. 57). 



Professor Schatjinsland lias sent me a series of twelve skins in all stages of growth and 

 plumage. The nestling as hatched is covered with dovm of a greyish-white colour, the basal 

 half of the down being dark sooty-brown. When we examine the next stage, in which the 

 young is covered with dark brown down, it becomes evident how the change from the downy 

 stage to the first plumage takes place without a real moult. The dark brown down when it 

 displaces the first nestling-down appears to be composed of integral downy plumes. As the 

 birds grow the down is pushed out further and further till we perceive that it is not composed 

 of integral plumes, but that it is attached to the end of the webs of the feathers. These 



Feather with down attached. 



downy filaments are then gradually worn off until we see the final feathers of the first white 

 plumage, which induced me to name the species D. immittabilis, to distinguish it from most 

 of the other Albatrosses, which had a first plumage different from that of the adult. I have 

 since, however, learnt that by far the greater number of the seventeen species of Albatrosses 

 have a similar metamorphosis of plumages to the present species. 



Professor Schauinsland describes the feet of the adult bird as pale bluish grey, the bill 

 yellowish with a greenish-grey tip ; and of a young bird in brown down the feet as dark 

 brownish grey, bill dark leaden grey. 



I have also received a series of eight eggs of D. immutabilis, which vary very much both 

 in shape and coloration. The two extremes are as follows : — 



1. Very elongate, length 111*5 mm., width G2'5 mm. ; ground-colour dirty white, marked 

 with numerous large and small blotches of a brownish-maroon colour, which are principally 

 massed at the two ends, though there arc also a few in the central zone. 



2. Very thick and short, length 100 mm., width 70; colour uniform brownish buff 

 without any markings whatever. 



The majority of the specimens before me are dirty white, with irregular patches and 



2 R 



