1044 SYSTEMATIC SYNOPSIS. — TUBINARES. 



some grayish-white. Plumage dull plumbeous or slaty-blackish, more smoky-brownish on 

 lower parts, lighter grayish-brown on greater wing-coverts ; wings and tail black. 2d primary 

 longest, 3d nearly equal, 1st longer than 4th. The general plumbeous or bluish-ashy cast of 

 the plumage is quite different from the sooty shade of 0. meJania, approaching the clearer ash 

 of 0. f areata. Length about 7.25; wing 5.25; tail 3.25, forked 0.60-0.90; tarsus 0.90; 

 middle toe and claw the same; bill 0.50; gape 0.75; height or width at base 0.20; nasal tubes 

 0.24. Coast of California, breeding on Farallone and Santa Barbara Islands. Egg dull 

 creamy white with fine reddish dots around great end. 



O. socorroen'sis. (Lat. of Socorro.) SocoRRO Fork-tailed Petrel. Similar to 0. homo- 

 chroa ; about same size ; wings longer ; tail shorter and less deeply forked ; feet smaller. 

 Lateral upper tail-coverts of the type specimen chiefly whitish, producing an evident spot on 

 each side of the rump ; no whitish under the wings, the under coverts being of the same color as 

 the under surface of the body. The general coloration darker than in 0. homochroa and more 

 as in 0. melania. Wing 5.55; tail 2.85, forked 0.40; culmen 0.55; nasal tube 0.27; tarsus 

 0.85; middle toe and claw the same. It is surmised that the lateral white spots on the upper 

 tail-coverts of the type may in other cases be united in one. Socorro Island, off the W. coast of 

 Mexico, and N. into our fauna; San Diego ; breeds on Coronados Islands and San Benito 

 Island, off the coast of Lower California, on the latter in June and July, with 0. melania and 

 Halocyptena microsoma ; egg single, laid in a burrow underground or among rocks, often that 

 deserted by Cassin's Auklet; shell smooth, not glossy, white, sometimes with pale or faint 

 specks of lavender and cinnamon about the larger end; average size 1.15 X 0.90. C H. 

 TowNSEND, Pr. U. S. Nat. Mus. xiii, 1890, p. 134; Salvin, Cat. B. Brit. Mus. xxv, 1896, 

 p. 352 ; A. 0. U. Suppl. List, Auk, Jan. 1897, p. 117, No. 108.1. 



O. furca'ta. (Lut. furcata, forked.) Gray Fork-tailed Petrel. Adult: Bluish-ash, 

 paler or whitish below and on greater wing-coverts, dusky about eyes; lesser wing-coverts 

 sooty; quills and tail brownish ; primaries pale or white on inner edges; outer web of outer 

 tail-feather white; bill and feet black. Length 8.00-9.00; wing 6.00-6.40; tail 4.00, forked 

 about 1.00 ; bill 0.60 ; tarsus 0.87 ; middle toe and claw the same. North Pacific coast, com- 

 mon, breeds on Aleutians and islands in the vicinity of Sitka; S. to Monterey. Young in 

 down light gray. Egg averaging 1.30 X 1.00, white with a pink flush when fresh, usually 

 found stained, or with fine spots about great end ; laid in underground burrows or holes in 

 rocks, chiefly in June. 



O. horii'byi. (To Admiral Hornby, R. N.) Hornby's Fork-tailed Petrel. Very 

 different from any of the foregoing ; -white below, with a distinct dark collar. Adult : Above 

 sooty-brown, paler and grayer on the upper back ; a whitish cervical collar across hind neck, 

 connecting with white of the throat ; hind head, nape, and about the eyes blackish ; front, lores, 

 and all under parts white, with the dark collar as said. Wings black, lightening to sooty- 

 gray on most of the coverts above and below ; tail dusky brown. Bill and feet black. Length 

 8.25; wing 6.75; tail 3.75; tarsus 1.00 ; middle toe and claw about the same; bill along cul- 

 men 0.60 ; along rictus 0.90. Northwest coast. I have never seen this rare species, of which 

 there are no specimens in this country; type in British Museum, figured by Salvin, Cat. B. 

 Brit. Mus. xxv, 1896, pi. 3. A. 0. U. Hypothetical List, No. 6. 



Subfamily OCEANITIN/E : Long-legged Stormy Petrels. 



Nasal tube and bill not peculiar, in comparison with Procellariince. Wings remarkably 

 distinguished in the whole family ProcellariideB by fewness of the secondaries — only 10 ; 1st 

 primary shorter than 2d, usually than 3d. Legs and feet very long, almost grallatorial ; leg- 

 bones longer than wing-bones ; tarsal bone at least twice as long as femur ; basal phalanx of 

 middle toe at least as long as next two joints ; outer and middle toes of approximately equal 



