DL'SKY PETREL. 191
Male; length, eleven inches; bill, bluish black; the tooth curved
and shining black; iris, brown. Head on the sides, below the level
of the eyes, white towards the back, where, and on the sides of the
neck, the black and white commingle in grey, slightly in the form of
bars. Head on the crown and sides, neck on the hack and nape,
black, ('bin, throat, and breast, white; the last-named somewhat dusky
behind the l e g s . Back, black.
The axillary plume is white. Greater and lesser wing coverts, white;
primaries, secondaries, and tcrtiaries, black; the primaries are blackish
grey underneath, darkest near the shall of each feather, being lighter
in colour over the outer part of each broad inner web. Tail, black
above, underneath, uniform leaden grey; upper tail coverts, black;
under tail coverts, white. Legs, much flattened at the sides, blackish
grey; toes and claws, blackish grey; webs, reddish brown.
