352 PEOCELLAE1ID.33. 



4. Oceanodroma socorroensis. 



Oceanodi'oma socorroensis, C. H. Toionsend, Pr. U.S. Nat. Mus. xiii. 

 p. 134 (1890). 



" Sp. cliar. Similar to 0. homochroa, Coues, but shorter lateral 

 upper tail-coverts chiefly greyish white (producing a distinct spot 

 on each side of the rump), longer upper tail-coverts smoky grey, and 

 under wing-coverts same colour as undei'parts of the body, instead 

 of being broadly margined with greyish white. 



'•'•Adult male (type, no. 11741)7, U.S. Nat. Mus.; Socorro Island, 

 off west coast of Mexico, March 8, 1889 ; C. H. Toivnsend). Above- 

 plain dark sooty-brown (almost 'clove' brown), becoming much 

 paler (light greyish brown or drab) on anterior portion of head, 

 including entire lores and forehead ; middle wing-coverts (old 

 feathers) also light greyish brown or drab ; greater coverts (new 

 feathers) smoke-grey ; edges of innermost secondaries (not tertials) 

 passing through smoke-grey into greyish white terminally (new 

 feathers) or through drab into brownish white (old feathers) ; 

 tertials, outermost secondaries, primaries, primary-coverts, &c. 

 sooty-black; lateral upper tail-coverts (except longer feathers) 

 greyish white (pure white basally), with concealed portion of inner 

 webs brownish grey ; longer upper tail-coverts uniform smoke-grey ; 

 tail sooty slate-black, the feathers whitish at extreme base ; under- 

 parts, including under wing- coverts, plain deep sooty-grey, paler 

 (light greyish brown or drab) on chin and throat, darker on under 

 tail-coverts ; bill, legs, and feet entirely black. Total length (skin) 

 6-80 inches, wing 5-55, tail 2-85, forked for 0-40, exposed culmeu' 

 0-58, nasal tube 0-27, tarsus 0-82, middle toe with claw O'So. 



" Hab. Socorro I., coast of Mexico. 



" This species is about the same size and proportions as 0. Jiomo- 

 cJiroa, and resembles it very closely in general coloration, but may 

 readily be distinguished by the very different coloration of the upper 

 tail-coverts and under wing-coverts. The shorter median upper 

 tail-coverts are apparently wanting, and it is possible that specimens^ 

 having these feathers present would show a continuous greyish- 

 white band across the basal portion of the upper tail-covert region : 

 in other words, what are in the type two lateral patches may in 

 perfect plumaged specimens have these two patches united." 



Mr. Eidgway has kindly furnished me with the above description 

 and note, there being no specimen of the species in the Museum 

 Collection. 



5. Oceanodroma fuliginosa. 



Sooty Petrel, Lath. Gen. Syn. iii. pt. 2, p. 409 (1785). 



Procellarla fuliginosa, Gm. Syst. Nat. i. p. 562 (1788) ; Lath. Ind. 



Om. ii. p. 825 (1790) ; Vieill. N. Diet. cTHist. Nat. xxv. p. 418 



(1817) ; id. Enc. Meth. p. 76 (1823). 

 Daption ? fuliginosum, Steph, in Shaw's Gen. Zool. xiii. p. 248 (1826). 

 Thalassidroma fuliginosa, Gray, Gen. Birds, iii. p. 648 (1844) ; id. 



Cat. Birds Trop. Is. Pac. p. 59 (1859). 

 Oceanodroma fuliginosa, Stejn. Pr. U.S. Nat. 3Ius. xvi. p. 620' 



(1893). 



