830 



U. S. p. R. K. EXP. AND SURVEYS — ZOOLOGY — GENERAL REPORT. 



The above is a copy of Mr. Gray's description of this species ; he states that '' iu form it 

 agrees best with Thai, furcata, but the coloration differs much in several particulars." 



Thalassidroma, Vigors. 

 THALASSIDEOMA LEACHII, Bon. 



Leach's Petrel. 



ProceUaria leachii, Temm. Man. II, 1820, 812. 



Thalassidroma leachii, Bon. Syn. 1828, No. 309.— Is. Consp. II, 1855, 193.— Nutt. Man. 11,1834, 326.— AuD. 



Orn. Biog. Ill, 1835, 434.— Ib. Birds Am. VII, 1844, 219 ; pi. cccclix. 

 ProceUaria bullockii, Flem. Br. Anim. 1828, 136, No. 219.— Vigors 

 ? " ProceUaria leucorrhoa, Vieillot." Eon. 

 Sp. Ce. — The plumage generally is sooty brown, darUjr on the crown ; primaries and tail brownish black ; wing coverts and 

 inner secondaries ashy gray ; rump, feathers of the sides adjoining it, and outer lower tail coverts, white ; bill black ; iris dark 

 brown ; tarsi and feet black. 



Length, 8 inches ; wing, 6^ ; tail, 3 ; bill, § ; tarsus ]. 



The female differs only in being rathei smaller. 



Ilab. — Atlantic coast from Massachusetts to Baffin's Bay, 



This is larger than Wilson's petrel, and has a much stronger bill ; it may be readily known 

 from it by its forked tail, and the interdigital webs being entirely black. 



List of specimens. 



THALASSIDROMA MELANIA, Bonaparte. 



The Black Stormy Petrel. 



ProceUaria melania, BoK. Comptes Rendus, Ac. Sc. XXVIII, 1854, 662. 

 Thalassidroma melania, Bon. Cons. Av. II, IS.W, 196. 

 " .' J'rucrlturiu Juliginosa, Lath. Not of Kuhl." Bon. 

 " ? ProceUaria scapxilala, Brandt." 

 Sp. Ch. — Entire upper plumage black ; wing coverts wholly black ; below fuliginous ; wings long ; tail short, but deeply 

 forked . 



Jlab. — Coast of California. 



It somewhat resembles Tlial. leachii, but is distinguished from this as well as all its congeners 

 by the absence of white on the rump, crissum, and on the wing coverts. 



