MONOGRAPH OF THE PETRELS. 



In the type-specimens of 0. markhami the dimensions are as follows : — Total 

 length about 9.0 inches ; culmen, 0.7 ; wing, 6.9 ; tail, 3.7 ; central rectrices, 2.4 ; 

 tarsus, 0.95 ; middle toe and claw, 0.95. 



It cannot, therefore, be doubted that O. markhami is a small form of 0. tristrami, 

 with a more slender foot ; but the number of specimens examined has been so few that 

 intermediate examples may yet be discovered, and the identity of the two species be 

 proved. It would not be surprising to learn that a species of Petrel which summers 

 in Japan should be found in winter off the coasts of Peru. 



Of the habits of 0. markhami nothing is known, and the only examples as yet 

 recorded are the two type-specimens in the British Museum, one of which has been 

 figured in the Plate. 



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