ORNITHOLOGICAL EXPLOKATIONS. 97 



30. Oceanodroma leucorhoa (Vieill). 



liil7.—Procellaria leucorhoa Vikill , N. Uict. d'llist. Nat., XXV, p. 422.— Blakist. & 

 Pryek, Il)i.s, 1878, 1). 218. -lid., Tr. As. Soc. Jap. VIII, 1880, p. 191.— lid., 

 ibid., X, lc82, p. lOU. — Blakist., Amend. List B.Jap., p. 35 (1884).— Seeb., 

 Ibis, 1884, p. 33. — Cijmochorea 1. Nelson, Cruise Corwin, p. 113 (1883). — 

 Turner, Auk, 1885, p. 158. 



1820. — Procellaria Ivachii Tem.m., Mau. d'Oiu., 2 ed., II, p. 812. — Schrenck, Reis. 

 Amurl., I, p. 515 (1860). — Thalassidroma J. Dall & Bannist., Tr. Chic. Ac, 

 1869, p. I, 303.— Dall., Avif. Aleut. Isl. west Unal., p. 8 (1874).— Taczan. 

 Orn. Fauu. Vost. Sibir., p. 66 (1877). — Id.. Bull. Soc. Zool. France, 1877, 

 p. 40. 



1826. — Procellaria jicJaoica Taja.., Zoogr. Ross. As., I, p. 316 (nee Linn.). 



1858. — Thalassidroma scapvlala Kittl., Denkw., II, p. 191 (Brandt, Icon. ined. pi. iv, 

 fig. 5). 



I can find no structnial character that will satisfactorily separate the 

 species which usually have been kept apart in the two genera Oceano- 

 droma and Cymochorea . Even the type of the latter, leucorhoa Vieill., 

 comes very close to Oceanodroma, but still more so does C. mclania Bp., 

 which has the graduation of the tail full}' as great as in O.furcata, and 

 the outer rectrices tapering toward the tip which is just perceptibly 

 more truncate than in the latter. This also has the notch of the trun- 

 cated end of the other rectrices a- trifle deeper than in typical Cymo- 

 chorea. 0. furcata, and G. melania also agree in the stoutness of the 

 bill. The tail of furcata is a little longer than in leticorhoa and melania 

 as compared with the wing, the formula of which is somewhat variable, 

 but, on the whole, identical in the three species. Even the coloration 

 is not so radically different as might appear at first sight, for the species 

 of Cymochorea are more or less washed with ashy gray, a color espe- 

 cially noticeable in fresh birds, while in okl museum specimens the color 

 turus brown, as I suppose, from oxydation of the fat contained in the 

 feathers, l^his is a fact which should alwa;) -s be borne in mind when 

 compariug old skins of water birds. The white feathers turn yellow, and 

 the gray ones become brownish, as I have invariably found it to be the 

 case in Larida\ Tubinarcs, and Alcida'. 



Oceanodroma, as the older name (1852), will therefore take precedence 

 over the younger, Cymochorea (1804), which can only be retained as a 

 subgeneric term designating the group, the dominating color of which is 

 fuliginous in contradistinction to the light ashy tint of the typical species 

 of Oceanodroma. 



The '■'■Malinka tschornaja Sturmofka,^^ or " small black Petrel," is on the 

 Commander Islands only known from Copper Island, where it breeds at 

 15861 Bull. 29 7 



