MONOGRAPH OF THE PETRELS. 



is disclosed when the bird is irritated or excited. The sides of both mandibles are 

 olive-grey changing to dull pinkish-yellow along the rami of the lower mandible, which 

 has its terminal expansion uniform slaty-black, and the culminicorn of a delicate lemon- 

 yellow. The sides of the mouth, both upper and under, are fringed with a yellow 

 membrane, which from the junction of the gape extends upwards and outwards for 

 about an inch. Iris of a lustrous coal-black with white eyelid beneath ; legs and 

 feet a greenish-grey, with flesh-coloured webs shaded with brown towards the outer 

 edge. Length, 36 inches ; expanse of wing, 7 feet 8 inches ; wing, 21 ; tail, 8.5 ; 

 tarsus, 3.4 ; middle toe and claw, 5.5 ; culmen, 5.3. 



The description and figure are taken from a specimen in the British Museum 

 presented by the Hon. Walter Rothschild. 



352 



