CLASSIFICATION. 



It should be noted that the German ornithologists, following Professor Reichenow, 

 adopt Boie's name Hydrobates, in preference to the Linnean name of Procellaria, the 

 type of which is considered by them to be Procellaria cequinoctialis. Vide infra, 

 pp. 169, 170. 



Key to the Species. 



a. Rump and upper tail-coverts white, the latter 

 tipped with black ; greater wing-coverts and 

 innermost secondaries edged with white ; under 

 wing-coverts sooty-black, with the ends of the 

 greater series white . . . . . . . . . . pelagica, p. 1 



6. Rump and upper tail-coverts pure white, not 

 tipped with black ; greater wing-coverts ashy- 

 brown, margined with white ; under wing-coverts 

 sooty-black, without any white . . . . . . teihys, p. 4 



II. — Halocyptena, Coues. 



Type 

 Halocyptena, Coues, Pr. Acad. Nat. Sci. Philad., 1864, pp. 79, 



90; Salvin, Cat. Birds Brit. Mus., XXV., p. 346 (1896) H. microsoma 



One species, H. microsoma (p. 6), from the coasts of Western America. 



III. — Oceanodroma, Reichenb. 



Oceanodroma, Reichenbach, Syst. Av., p. iv. (1852) ; 

 Coues, Pr. Acad. Nat. Sci. Philad., 1864, p. 74; 

 Salvin, Cat. Birds Brit. Mus., XXV., p. 347 (1896). . 



Cymochorea, Coues, Pr. Acad. Nat. Sci. Philad., 1864, p. 75. . 



Type 



0. furcata 

 0. leucorrhoa 



Key to the Species. 



a. Plumage sooty-black, with more or less of an ashy 

 shade ; under-parts sooty. 



a'. Upper tail-coverts more or less white, not uniform 

 with the back. 



a" 



Greater coverts ashy -brown, paler than the j leucorrhoa, p. 8 

 rest of the wing ; upper tail-coverts white, i beali, p. 11 



more or less ashy, sooty-brown, or blackish 

 at the ends, or in the centres 



beldingi, p. 12 

 Jecedingi, p. 13 



XXXV 



