OCEANITES. 71 



wing 6.90, tail 3.80 (forked for about 1.20), tarsus 1.00. 

 Ilab. Coast of Peru, 



O. markhami (Salt.). Markham's Petrel.^ 

 d^. Wing less than 6.00 ; tarsus less than 1.00. 



Smoky plumbeous, the wing-coverts lighter and more brown, 

 quills and tail dusky, rump and upper tail-coverts ashy 

 plumbeous ; wing 5.30-5.40, tail 3.30-3.50 (forked for .70- 

 .90), tarsus .80-90. Hab. Coast of California. 



108. O. homochroa (Coues). Ashy Petrel. 

 a}. Upper tail-coverts white. 



h^. Upper tail-coverts without black tips ; tail-feathers grayish at base ; uni- 

 form sooty, darker above ; upper tail-coverts white, usually more or less 

 mixed with grayish; length 7.50-8.90, wing 6.00-6.30, tail 3.50-4.00 

 (forked for .80-.90), tarsus .90-95 ; feet (including webs) entirely black. 

 Egg 1.33 X -97. Hab. Seas of the northern hemisphere. 



106. O. leucorhoa (Vieill.). Leach's Petrel. 

 h^. Longer upper tail-coverts broadly tipped with black ; tail-feathers exten- 

 sively pure white at base ; bill and feet (including webs) entirely black ; 

 wing 5.80-6.30, tail 3.00-3.15 (forked for .20-.30), tarsus .85-.90. Hab. 

 Sandwich Islands. 



O. cryptoleucura Kidgw. Sandwich Island Petrel.^ 



Genus OCEANITES Keyserling & Blasius. (Page 56, pi. XVII., fig. 3.) 



Species. 



Common Characters. — Sooty blackish, lighter beneath, the tail and quills 

 nearly or quite black ; upper tail-coverts white. 



a}. Belly entirely dusky ; webs of feet mostly yellowish ; tail even or very slightly 

 emarginated; length about 7.00-7.25, wing 5.70-6.20, tail 3.00-3.25, tarsus 

 1.30-1.35. Hab. Cosmopolitan (on the high seas). 



109. O. oceanicus (Kuhl). Wilson's Petrel. 

 «^ Belly white ; webs of feet apparently wholly dusky ; tail distinctly emarginated; 

 wing 5.20, tail 2.30 (forked for about .30), tarsus 1.15. Hab. Coast of Chili. 



O. gracilis (Elliot). Graceful Petrel.* 



Genus CYMODROMA Eidgwat. (Page 56, pi. XV., fig. 3.) 



Species. 



Common Characters.— Head, neck, breast, and upper parts dusky, varying 

 from brownish black to plumbeous, the feathers of back and scapulars sometimes 

 (in fresh plumage) margined terminally with ashy whitish. 



1 Cymochorea markhami Salt., P. Z. S. 1883, 430. 



2 Cymochorea cryptoleucura RiDGW., Proc. U. S. Nat. Mus. iv. 1882, 337 ; Water B. N. Am. ii. 1884, 406. 



3 Thalassidroma gracilis Elliot, Ibis, Oct. 1859, 391. Oceanitea gracilis Coues, Pr. Ac. Nat. Sci. Phil. 

 1864, 85. 



