MONOGRAPH OF THE PETRELS. 



The following description is taken from the specimen in the British Museum : — 



Adult. General colour above sooty-black, the upper tail-coverts conspicuously 

 white ; wing-coverts sooty-black like the back, the greater series somewhat browner 

 and with faint hoary margins ; quills and tail-feathers sooty-black, the latter white at 

 the base, the shafts also white at the base ; head and neck all round, fore-neck and 

 chest, sooty-black ; the throat white, mottled with sooty-black tips to the feathers ; 

 remainder of under-surface from the chest downwards pure white, streaked on the 

 breast and sides of the body with black longitudinal centres, widening out towards the 

 ends ; abdomen and under tail-coverts white, the latter also with black spots at the 

 ends ; axillaries white, as also the under wing-coverts, which have a very broad band 

 of sooty-black round the bend of the wing ; " bill and feet, including interdigital 

 membrane, blue-black, without any spots ; iris dark brown " (Peale). 



Total length, about 7 inches ; culmen, 0.6 ; wing, 5.5 ; tail, 2.7 ; tarsus, 1.3 ; middle 

 toe and claw, 1.1. 



The figure in the Plate was drawn from the specimen in the Paris Museum, and 

 Salvin was indebted to Professor Milne-Edwards for the loan of it and several other 

 rare species. 



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