MONOGRAPH OF THE PETRELS. 



except on the culmen, where it is more yellow, particularly at the base ; the upper 

 mandible surrounded at the base by a narrow belt of black, which also extends on 

 each side of the culmen to the nostrils, base of the lower mandible surrounded by a 

 belt of orange, reaching to the corner of the gape. Feet bluish white ; irides brown " 

 (Gould). 



Total length, 31 inches ; wing, 23 ; tarsus, 3.7 ; middle toe and claw, 5.9. 



The sexes differ but little in colour ; the female may, however, be distinguished 

 by its smaller size, and the young by the bill being clouded with dark grey. 



350 



