PROCELLARIIDH, PETRELS.—GEN. 305, 306, 307. 329 
305. Genus CYMOCHOREA Coues. 
Leach’s Petrel. Coloration as in the last species, 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 6-64; tail 
3-34, forked; tarsus about 1; middle toe and claw the same; bill 3, strong. 
Both coasts; abundant on the Atlantic. P. lewcorrhoa Vinitu., Nouv. Dict. 
xxv, 422; ©. leucorrhoa Cours, 1. c. 76. Thal- 
assidroma leachiti Nutt., li, 326; Aup., vii, 219, 
pl. 459; Lawr. in Bp., 830. . . LeucORRHOA. 
Black Petrel. Coloration as in the last species, 
but no white anywhere. Very large; 9; extent 
184; wing 62; tail 4, forked an inch or more; 
tarsus 14; bill 2. Coast of California. _Pro- Fic. 211. Black Petrel. 
cellaria melania Bonar., Compt. Rend. 1854, 662; C. melania Cours, 
I. c. 76 (described from No. 13,025, Mus. §. I.).. . . . MBELANIA. 
Ashy Petrel. Somewhat similar to the last, like it having no white any- 
where, but plumbeous rather than fuliginous, and much smaller. Length 
ubout 74; wing about 5; tail 34, forked about $ an inch; tarsus under an 
inch; bill $. California. Thalassidroma melania Lawr. in Bp., 829, pl. 90 
(nec Bonar.). C. homochroa Cours, l. c. 77; Exxtot, pl. 87. HoMOCHROA. 
306. Genus OCEANODROMA Reichenbach. 
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 32, forked; bill 3; tarsus §. N. Pacific Coast, common. Cass., 
Wi 2945 pl.47 3) Lawr. in) Bp., 829. . . - 2.)  HUROATAS 
Hornby’s Petrel. “Front, Alleles: throat, collar punt 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 Bp., 829. . . . HORNBYI. 
307. Genus OCEANITES Keys. and Blas. 
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 ; tibix 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; wing about 6; tail 3, nearly even; tarsus 1}; 
middle toe and claw 14; bill only 4. Atlantic Coast, common. Proc. 
oceanica Kunt, Monog. 136, pl. 10, f. 1; Oceanites oceanica Cougs, l. ¢. 
2; Proc. pelagica Wits., vii, 90, pl. 60, f. 6; Thalassidroma wilsont 
Nurv., ii, 322; Avp., vii, 223, pl. 460; Lawr. in Bp., 831. . OCEANICA. 
KBY TO N. A. BIRDS. 42 
