DUSKY PETREL. 621 



swam lightly, and dipped their bills frequently in the water, in the man- 

 ner of Mergansers. 



I preserved the skins of the four specimens procured. One of them 

 1 sent to the Academy of Natural Sciences of Philadelphia, by Captain 

 John R. Butler, of the ship Thalia, then bound from Havannah to 

 Minorca. Two others were presented to my excellent friend Dr Traill, 

 on my first becoming acquainted with him at Liverpool. 



I found the wings of this species strong and muscular for its size, this 

 structure being essentially requisite for birds that traverse such large ex- 

 panses of water, and are liable to be overtaken by heavy squalls. The 

 stomach resembles a leather purse, four inches in length, and was much 

 distended with fishes of various kinds, partially digested or entire. The 

 oesophagus is capable of being greatly expanded. Some of the fishes were 

 two a,nd a half inches in length, and one in depth. The flesh of this Pe- 

 trel was fat, but tough, with a strong smell, and unfit for food ; for, on 

 tasting it, as is my practice, I found it to resemble that of the porpoises. 

 No difl^erence is perceptible in the sexes. 



While on board the United States' Revenue Cutter the Marion, and 

 in the waters of the Gulf Stream opposite Cape Florida, I saw a flock of 

 these birds, which, on our sailing among them, would scarcely swim off 

 from our bows, they being apparently gorged with food. As we were 

 running at the rate of about ten knots, we procured none of them. I 

 have also seen this species off" Sandy Hook. 



Procellabia obscura, Lath. Ind. Ornith. vol. ii. p. 828. 



PuFFiNus OBscuRus, Ch. Bonaparte, Synops. of Birds of the United States, p. 371- 



Dusky Petrel, Lath. Synops. vol. iv. p. 416 Nuttall, Manual, vol. ii. p. 337. 



Adult Male. Plate CCXCIX. 



Bill about the length of the head, straight, somewhat cylindrical, the 

 tips curved. Nostrils tubular, separate, inclosed in a horny sheath, and 

 dorsal, the outline straight, curved on the unguis, the sides nearly erect, 

 convex, the edges sharp, hard, and inflected, the tip decurved, strong. 

 Lower mandible straight, the angle very narrow and extending nearly to 

 the tip, the dorsal line beyond it decurved, the sides convex and inclining 

 inwards, the edges sharp and inflected. 



Head of moderate size. Neck of ordinary length ; body ovate. Feet 

 stout ; tibia bare a short way above the joint ; tarsus of moderate length. 



