70 . NORTH AMERICAN BIRDS. 



a 1 . Longer upper tail-coverts broadly tipped with black ; under side of wing with 

 more or less of white; tail even, or slightly rounded ; length 5.50-5.75, wing 

 4.50-4.90, tail 2.40-2.60, culmen .40-.50, tarsus .90, middle toe .60-.65. Egg 

 1.09 X -83. Sab. North Atlantic, south to Newfoundland Banks and 

 western coast of Africa 104. P. pelagica Linn. Storm Petrel. 



a 1 . Longer upper tail-coverts entirely white ; no white on under side of wing ; tail 

 emarginated ; wing 5.20, tail 2.40, the middle feathers .20 shorter ; tarsus .85, 

 middle toe (with claw ?) .70. Sab. Vicinity of the Galapagos Islands. 



P. tethys Bonap. Galapagos Storm Petrel. 1 



Genus OCEANODROMA Eeichenbach. (Page 56, pi. XVII., figs. 1, 2.) 



Species. 



Common Characters. — Above dusky or grayish, with or without white on 

 upper tail-coverts ; lower parts uniform bluish gray or sooty, or white interrupted 

 by a grayish band across chest. 



a 1 . No white on upper tail-coverts. 



b 1 . A white collar round hind-neck. 



Lower parts white, with a grayish collar across chest; upper parts 

 grayish, the quills blackish, the forehead and sides of head white ; 



length about 8.25, wing ?, tail 3.75, tarsus 1.00. Sab. North 



Pacific ("Northwest coast of America"). 



— . O. hornbyi (Gray). Hornby's PetreL 

 V. No white collar round hind-neck. 



c. 1 Color bluish gray, above and below. 



Uniform bluish gray, fading to white on chin, throat, and under 

 tail-coverts; orbital region, longer scapulars, innermost wing- 

 coverts, anterior and outer lesser wing-coverts, together with 

 quills, dusky ; other lesser coverts, middle and greater coverts, 

 and tertials, broadly edged with ashy white ; length 8.00-9.20, 

 wing 5.90-6.40, tail 3.75-4.00 (forked for about 1.00). Egg 1.37 

 X 1-03. Sab. North Pacific, south on the American side to 



Oregon 105. O. furcata (Gmel.). Fork-tailed Petrel. 



c a . Color sooty brownish or dusky, above and below. 

 d 1 . Wing more than 6.50 ; tarsus 1.00, or more. 



e 1 . Sooty blackish, lighter and browner beneath, the greater wing- 

 coverts and outer webs of tertials light grayish brown; 

 wing 6.80, tail 3.90 (forked for about 1.20), tarsus 1.20. 

 Sab. Coast of Mexico, north to Lower California. 



107. O. melania (Bonap.). Black Petrel. 



e?. Sooty slate-color, the head, including throat, appreciably paler 



and more plumbeous ; greater wing-coverts light grayish ; 



1 Proeellaria tethyt Bonap., Comp. Rend, xxxviii. 1854, 662 ; Conap. ii. 1857, 197. Salt. Trans. Zool. Soo. 

 Lond. ix. pt. ix. 1875, 507, pi. 88, fig. 2. 



