52 BULLETIN" 133, UNITED STATES NATIONAL MUSEUM 



hurried into dark corners; others attempted to clamber into the 

 lighted passageAvays, pulling themselves over the raised thresholds 

 of the doorways by aid of their bills. Occasionally one gave a 

 raucous call, with widely opened mouth. All resented handling by 

 biting savagely. Wlien thrown overboard they fluttered heavily 

 down to the water or turned to swing in again toward the ship. 

 One that I skinned proved to be an immature female, and all of 

 those handled appeared to be young birds. During the daytime 

 they were observed resting on the water or scaling over the waves, 

 when they were recognized by the light under wing coverts that 

 showed in contrast with their otherwise somber coloration. 



PROCELLARIA AEQUINOCTIALIS AEQUINOCTIALIS Linnaeus 



ProceUaria aequinoctialis Linnaeus, Syst. Nat., ed. 10, vol. 1, 1758, p. 132. 

 ( Cape of Good Hope. ) 



This species, noted commonly at sea from June 15 to 20, 1920, 

 from latitude 22° 30' S. to the mouth of the Rio de la Plata, fre- 

 quently came close to the stern of the steamer in following over the 

 wake. The birds circled with set wings, scaling swiftly along, often 

 tilting sideways at such an angle that they seemed about to over- 

 turn. As their momentum slackened they rose again Avith a few 

 quick wing strokes, and then swinging in a short circle scaled away 

 once more. Occasionally they alighted on the water, where they 

 floated high like gulls. They were characterized by sooty black 

 plumage, rounded tail, and a bill marked with yellow and slaty 

 black. The silence of these great sea birds, in time, impresses one 

 as uncanny. 



On November 3 and 4 many were circling just outside the breakers 

 below Cabo San Antonio, on the eastern coast of Buenos Aires, 

 during a heavy gale. At times they swung in to w^ithin 100 meters 

 of the shore. On a dead bird picked up on the beach at La Paloma, 

 Rocha, Uruguay, on January 23, 1921, the culmen measured 50.5 mm., 

 while there was a small white interramal chin spot. The head of 

 this specimen was preserved. 



OCEANODROMA TETHYS (Bonaparte) 



Thalassidroma tethys Bonaparte, Journ. fiir Ornith., 1853, p. 47. (Gala- 

 pagos Islands.) 



An immature female Galapagos petrel came aboard ship on the 

 evening of May 9, 1921, when we were about 10 miles west of La 

 Plata Island, on the coast of Ecuador. As Loomis^^ has indicated, 

 the tail in this species is slightly forked, the incision in the present 

 specimen amounting to 5 mm., so that tethys seems to belong in the 



"Proc. California Acad. Scl., ser. 4, vol. 2, pt. 2, no. 12, Apr. 22 1918, p. 153. 



