MONOGRAPH OF THE PETRELS. 



on Midway, Lisiansky, Necker and Bird Islands, where D. nigripes is likewise found, 

 and a specimen in the Tring Museum is from the Japanese island of Miyakeshima 

 (Bull. B. 0. C, III., p. xlvii., 1894). Mr. A. W. Anthony has recorded an example 

 obtained between San Geronimo Island and Guadalupe Island, off Lower California 

 (Auk, XV., p. 38, 1898). 



Adult. General colour above dark brown with a shade of grey, and faded 

 edges to the feathers ; scapulars like the back, but a little darker ; wings darker and 

 blacker than the back ; quills blackish, the outer primaries with yellowish shafts, 

 the secondaries with more or less white towards the base of the inner web ; lower back 

 and rump brown, with a distinct shade of grey, the upper tail-coverts white, 

 with a more or less conspicuous brown spot at the ends, especially on the longer ones ; 

 tail-feathers blackish brown with a little white at the extreme base, and with 

 yellowish shafts to the centre feathers ; head and neck all round as well as the entire 

 under-surface of body, pure white, including the under tail-coverts ; under wing- 

 coverts white, with a broad blackish band round the bend of the wing ; outermost 

 ■ hypopteral plumes greyish-brown, with white tips, the innermost with the greater part 

 of the outer web smoky-brown, the middle ones pure white ; quills dusky-brown 

 below, greyer on the inner web ; " bill grey, darker at base, tip blackish brown, 

 base of under-mandible pale yellow ; tarsi and feet fleshy-pink ; iris brown " 

 (W. Palmer). Total length, about 28 inches ; culmen, 4.2 ; wing, 19.0 ; tail, 5.6 ; 

 tarsus, 3.1 ; middle toe and claw, 4.2. 



The sexes are alike in colour and the first plumage (which is dark in most 

 Albatroses) is similar to that of the adult bird, the breast and entire under parts being 

 pure white : hence the specific name of immutabilis. 



The nestling is covered with down of a brown colour ; the bill is blackish-brown, 

 and the iris is brown also. 



The description of the adult bird and the figure in the Plate are taken from a 

 specimen presented to the British Museum by the Hon. Walter Rothschild. There is 

 an excellent figure of it in his great work on the " Avifauna of Laysan." 

 Our artist has somewhat exaggerated the yellow tinge on the back of the head and 

 neck, and also on the under surface of the body. 



338 



