PROCELLAEIID^, PETRELS. GEN. 305, 306, 307. 329 



305. Genus CYMOCHOREA Coues. 

 if" Leach's Petrel. Coloration as in the last si3ecies, with conspicuous white 

 upper tail coverts, but apt to be lighter — rather of a grayish or even 

 ashy tint on some parts. Much larger : length about 8 ; wing 6-6^ ; tail 

 S-3i, forked; tarsus about 1 ; middle toe and claw the same ; bill §, strong. 

 Both coasts; abundant on the Atlantic. P. leucorrJioaYiKiLL,., Nouv. Diet. 

 XXV, 422 ; 0. leucorrhoa Coues, L c. 76. Thal- 

 assidroma leacliii Nutt., ii, 326; Aud., vii, 219, 

 pi. 459; Lawe. in Bd., 830. . . leucorrhoa. 

 K^^'Cl Black Petrel. Coloration as in the last species, 

 but no white anywhere. Very large ; 9 ; extent 

 18J ; wing 6| ; tail 4, forhed an inch or more ; 



tarsus 1^ ; bill f . Coast of Calif(n-nia. Pro- fig. 211. Black Petrei. 

 cellaria melania Bonap., Compt. Rend. 1854, 662; O. melania Coues, 



I. c. 76 (described from No. 13,025, Mus. S. I.) melania. 



^■■■'\^) Ashy Petrel. Somewhat similar to the last, like it having no Avhite any- 

 where, but plumbeous rather than fuliginous, and 7nuch smaller. Length 

 about 7 J ; wing about 5 ; tail 3^, forked about J an inch; tarsus under an 

 inch; bill ^. California. Thalassidroma melania Lawr. in Bd., 829, pi. 90 

 (nee Bonap.). C. homocliroa Coues, I. c. 11 ; Elliot, pi. 87. homochroa. 



306. Genus OCEANODROMA Reichenbaeh. 



^-^ / Fork-tailed Petrel. Bluish-ash, paler below and on the greater wing 



coverts, dusky around the eye ; quills and tail brownish, outer web of the 



external tail feather white ; bill black ; feet dark. Length about 8 ; wing 



6; tail 3^, forked; bill %; tarsus J. N. Pacific Coast, common. Cass., 



111. i, 294, pi. 47; Lawr. in Bd., 829 furcata. 



(^'^/ > Hornhi/s Petrel. "Front, cheeks, throat, collar round hind part of neck, 

 breast and abdomen, pure white," quills black, other parts dark gray. Size 

 of the last. N.W. coast. I have never seen this species, of which there are 

 not to my knowledge any specimens in this country. Thalassidroma hornbyi 

 Gray, Proc. Zool. Soc. 1853, 62; Lawr. in Bd., 829. . . . hornbyi. 



307. Genus OCEANITES Keys, and Bias. 



J' ^3 Wilson's Petrel. Dark sooty brown, pale gray on the wing coverts; the 

 upper tail coverts, and frequently the crissum and sides of rump and base of 

 tail, white; bill and feet black, but webs with a yellow spot. Legs very 

 long ; tibiffi bare an inch or more ; tarsi "booted," much longer than the toes ; 

 claws flat, obtuse ; bill small and weak ; hind toe very minute, liable to be 

 overlooked. Length 7-8 ; Aving about 6; tail 3, nearly even; tarsus 1^; 

 middle toe and claw IJ ; bill only ^. Atlantic Coast, common. Proc. 

 oceanica Kuhl, Monog. 136, pi. 10, f. 1 ; Oceanites oceanica Coues, I. c. 

 82; Proc. pelagica Wils., vii, 90, pi. 60, f. 6; Thalassidroma ivilsoni 

 Nutt., ii, 322 ; Aud., vii, 223, pi. 460 ; Lawr. in Bd., 831. . oceanica. 



KEY TO N. A. BIRDS. 42 



