1872.] FROM THE PELEW AND MACKENZIE ISLANDS. 109 



Upper parts, including wing and tail, sooty black ; this colour ex- 

 tends from the angle of the mouth, bordering the eye beneath, to the 

 middle of the ear-region ; the sides of the neck and breast sooty grey- 

 ish black, tipped narrowly with whitish ; remainder of the underparts 

 white ; the central and lateral under tail-coverts sooty black, some 

 of the former very narrowly margined at the apex with white ; the 

 anterior central under tail-feathers greyish black, towards the basal 

 half whitish, and with broader white apical margins; under wing- 

 coverts white, along cubitus and manus bordered with sooty-black 

 feathers ; the remiges on the inner web towards the base become paler 

 brownish ; the tectrices of the secondaries very faintly and narrowly 

 tipped with whitish ; there is a slight indication of a white line bor- 

 dering the eye underneath ; bill hornish, dark brown, tip paler ; in- 

 side of tarsus, toes, and membranes pale hornish yellow ; external toe 

 and outside of tarsus dark blackish brown, lighter, into brownish 

 yellow towards the basal half of tarsus ; nails blackish ; the tail is 

 somewhat cuneate, the tips of the quills reach to about one third 

 from the end of the tail. 



In former collections from the Pelews we examined five specimens ; 

 this last collection contains six adult and two young examples, ail 

 collected by Capt. Heinsohn. 



There exists little variation amongst these specimens ; we notice 

 only that in some specimens the under tail-coverts are throughout 

 sooty black, in others the anterior lateral under tail-coverts are white 

 at the greater basal portion of the inner web. The very faint whitish 

 tips of the tectrices of the secondaries are in some specimens almost 

 wanting; the sides of the thighs have sometimes a greyish dark 

 mark. 



The two nestlings are clothed uniformly with thick greyish- brown 

 down, changing on the middle of the underparts into white. Co- 

 loration of feet as in old birds. The young from M'Kean's Island 

 are precisely similar. 



Through the kindness of Dr. Cabanis we received the type of our 

 P. dichrous from M'Kean's Island (collected by Dr. Graffe), and now 

 deposited in the Berlin Museum. After a careful comparison, we 

 have not the slightest doubt as to its identity with Pelew specimens. 

 The type specimen of P. dichrous, the only one we ever received from 

 the Central Pacific, has a little shorter wings. The anterior lateral 

 under tail-coverts are white on the greater portion of the inner web, 

 just as in some specimens from the Pelews. The coloration is quite 

 the same. 



In our previous memoirs on the Pelew birds we took this Petrel, 

 although with some doubt, for P. opisthomelas, noticing the consi- 

 derably smaller size. Having now examined about a dozen specimens 

 from the Pelews, in comparison with the type specimen, we find the 

 smaller size to be constant, and cannot unite them with those noticed 

 by Mr. Coues, after the two specimens from Cape St. Lucas, Lower 

 California (coll. Xantus) in the collection of the Smithsonian Institu- 

 tion, and the figure given by Mr. Elliot (Introd. B. N. Am. fig. head, 

 natural size). In coloration there seems to exist no considerable 



