WILSON'S PETREL 543 



Adult winter, male and female. Similar to the nuptial 

 plumage. 



Immature, male and female. Resembles the nuptial 

 plumage. 



BEAK. Black. 



FEET. Black. 



IRIDES. Brown. 



EGG. " Exactly like the egg of Leach's Petrel, white, 

 with an indistinct zone of light red, and faint purplish under- 

 lying dots round the larger end" (Ogilvie-Grant, 'Ibis,' 1896, 

 p. 54) : clutch, one. 



AVERAGE MEASUREMENTS. 



TOTAL LENGTH 7 in. Female larger. 



WING 6-1 



BEAK ... ... 0*8 



TARSO-METATARSUS ... 0'82 ,, 



EGG 1-3 x '96 in. 



Allied Species and Eepresentative Forms. The follow- 

 ing list of Petrels with forked tails, which speaking gener- 

 ally are inhabitants of some part or other of the Pacific 

 Oceans may here be included: 0. macrodactyla ; 0. socor- 

 rcensis ; 6. fuliginosa ; 0. melania ; 0. markhami ; 0. 

 tristrami ; 0. homochroa ; 0. monorhis ; 0. hornbyi ; and 

 O. furcata. 



