DUSKY PETREL. 131 
‘cold pale moon’ being more suitable to their habits than the 
bright glare of the sun. 
They feed on fish, and almost any kind of food. 
The egg, for one only is laid, is pure white. 
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 back, and nape, black. Chin, throat, 
and breast, white; the last-named somewhat dusky behind the 
legs. Back, black. 
The axillary plume is white. Greater and lesser wing coverts, 
white; primaries, secondaries, and tertiaries, black; the pri¬ 
maries are blackish grey underneath, darkest near the shaft 
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. 
