90 PROCEEDINGS OF THE ACADEMY OP 



Bp). Bluish gray, lighter beneath, passing into black around the eyes and on 

 the primaries. 



0. Hornbyi, Bp. ex Gray. (Thai. Horribyi, Gray). Ashen gray, passing 

 into blackish on the wings ; with the front, cheeks, a nuchal collar, and the 

 under parts generally, white. 



2. Genus Cymochorea, Coues. (= Thalassidroma, Auct. sed non Tig.) Bill 

 comparatively large and strong. Wings much longer than in preceding genus ; 

 second primary much the longest; first longer than fourth. Colors uniform or 

 nearly so. 



C. leueorrhoa, Coues ex Vieill. (Proc. leucorrhoa, Vieill. Thai. Leachii, 

 Temm. et Auct.) Fuliginous, with a white rump and crissum. 



C. melania, Coues ex Bp. (Thai, melania, Bp. nee Lawr.) Entirely fuligin- 

 ous brownish black. Total length about 9.00 inches ; wing 6.75; tail 3.90; 

 bill .60; tarsus 1.20. 



C. homochroa, Coues. (Thai, melania, Lawr. nee Bp.) Entirely brownish 

 black, with a cinereous tinge. Length about 7.25 inches; wing 5.00; tail 

 3.25; bill .50; tarsus .90. 



II. Tail cuneate. 



3. Genus Halocyptena, Coues, nov. gen. Bill about half the tarsus' 

 Wings exceedingly long ; second primary longest ; third nearly equal; fourth 

 about equal to first. Tail very long. 



H. microsoma, Coues, nov. sp. Smallest known Petrel. Entirely fuliginous 

 black. Length 5.75 inches ; wing 4.75! tail 2.50; bill .48 ; tarsus .90 ; mid- 

 dle toe and claw .82. 



III. Tail square, or slightly rounded. 



4. Genus Procellaria, Linn. [Emend.] (Thalassidroma, Vig.) Bill very 

 small and short, robust ; wings and tail moderately long ; third primary 

 nearly equal to the second; first shorter than fourth. Middle toe a little less 

 than tarsus. 



P. pelagica, L. nee Wils. (Uydrobates pelagica, Boie. Thalassidroma pelagica, 

 Vigors et auct.) The white upper tail coverts tipped with black. 



?. P. tethys, Bp. The upper tail coverts entirely white. 



?. P. Ivgubris, Natterer. Somewhat larger, with a more robust bill. 



?. P. melitcnsis, (Schembri). 



P. nereis, Bp. ex Gould. (Thai, nereis, Gould.) Head, neck, upper part of 

 back, fuliginous brown with a cinereous hue, which, on the back, wing, and 

 tail coverts, lightens into a clear bluish ash. Primaries brownish black ; tail 

 feathers light ashen blue, deepening into black towards their tips- Beneath 

 white, with some bluish shaft lines. 



P. fasciolata, Coues ex Tschudi. (Thai. fasciolata, Tsch.) Bill, feet, head, 

 slightly rouunded tail, and underparts to the vent black. Circumanal region 

 pure white; the back rusty brown, as are the superior surfaces of the wings. 

 A whitish brown streak from the back to the bases of the primaries half an 

 inch broad. 



Group B. Legs extremely long and slender. Tarsus much exceeding the 

 middle toe and claw. Tibiae naked for a great portion of their length. Claws 

 depressed, obtuse, rounded. More or less variegated in colors. 



1. Tail slightly rounded. Tarsal scutella fused together. 



VI. Genus Oceanites, Keys et Bias. Bill small and weak. Nasal tubes 

 perfectly horizontal. Wing exceedingly long; second primary much the 

 longest ; first fully equal to the third ; fourth much shorter. Toes very 

 long, but only two-thirds the tarsus. Hallux exeedingly minute. 



Oceanites oceanica, (Kuhl). Proc. pelagica, Wils. nee Linn. P- oceanica, 

 Kuhl et Banks. Thai, oceanica, Gray. Thai. Wilsoni, Bp. olim. Oceanites 

 Wilsoni, Keys et Bias.; Bp. quoque, nuper. Oceanites oceanica ?) 



[March, 



