WHITE -CAPPED ALBATROSS. 53 



Genus DIOMEDELLA. 



Diomedella Mathews, Birds Austr., Vol. II., pt. 3, p. 275, Sept. 20th, 1912. Type (by 

 original designation) : Diomedea cauta Gould. 



Larger Mollymawks with long bills, long wings, medium tails and stout legs 

 and feet. 



The bill shows a space between the culminicorn and the latericorns posterior 

 to the nostrils, and also between the culminicorn and the frontal feathers ; these 

 spaces are diminished in extent in some of the forms but the culminicorn never 

 broadens out, or conversely, narrows as in forms of Thalassarche. In the lower 

 mandible the bar at the base shows an entry into the edge, not bounding it as in that 

 genus. The wing is longer, but the tail is practically the same length. The feet 

 are larger but of same nature. 



Coloration similar to that of Thalassarche. 



This genus approximates in some items to Diomedea. 



41. Diomedella cauta. WHITE-CAPPED ALBATROSS. 



Gould, Vol. VII., pi. 40 (pt. xv.), June 1st, 1844. Mathews, Vol. II., pt. 3, pi. 100, Sept. 

 20th, 1912. 



Diomedea cauta Gould, Proc. Zool. Soc. (Lond.), 1840, p. 177, July 1841 : Bass Straits. 



Diomedella cauta rohui Mathews, Austral Av. Rec., Vol. III., pt. 3, p. 55, April 7th, 1916 : 



Sydney, New South Wales. 



Diomedella cauta wallaca Mathews, ib., pt. 6, p. 160, June 25th, 1918. New name for 



preceding. 



DISTRIBUTION. Eastern and Southern Australian Seas. 



Adult male. Upper back slate-grey, with white bases and pale margins to the 

 feathers ; scapulars ash-brown, white only at the extreme base ; wing-coverts 

 dark brown with white bases ; the smaller coverts showing pale edges ; primary- 

 coverts and primary-quills dark brown, the latter with white shafts and white on the 

 inner webs ; secondaries also dark brown, with the basal portion of the inner webs 

 white ; tail-feathers hoary -grey with white shafts ; a narrow eyebrow and a spot in 

 front of the eye black, becoming pale towards the base of the bill, a patch behind the 

 eye including the ear-coverts washed with plumbeous -grey ; head and neck all 

 round white, as also the under-surface of body, including the axillaries, under wing- 

 coverts white, the marginal ones blackish ; bill bluish horn, lower mandible darker, 

 upper mandible with a narrow belt of black and on each side of the nostrils ; base 

 of lower mandible with a belt of orange reaching to the corner of the gape ; iris 

 brown ; feet bluish-white. Total length 987 mm. ; culmen 137, wing 590, tail 204, 

 tarsus 86. 



Adult female. Similar to the adult male (? smaller) but with the grey on the 

 sides of the neck paler, and the yellow markings on the bill duller. 



Immature. Undescribed . 



Nestling. Covered with white down ; bill black. 



Nest. Composed of chocolate-coloured soil, largely mixed, when in a wet 

 state, with rootlets and other vegetation, which gives it the appearance of peaty 

 substance. It is smoothed over and holds together fairly well, varying in height 

 externally from 3 to 7 inches. The measurements of an average nest are as follows : 

 internal diameter 11 1 inches, external diameter 14, basal diameter 16| ; external 

 height 5 1, internal depth 3|. 



Egg- Clutch, one ; creamy-white, freckled more or less with reddish -brown 

 surface-markings on the larger end. In some cases these markings were minute, 

 numerous, and almost continuous, while in others they were much larger and darker, 

 on a slightly reddish ground, but there were various gradations between the two 



