86 PROCEEDINGS OF THE ACADEMY OF 



The plumage is fuliginous black ; the lower part of the breast, the belly, the 

 sides under the wings, both tail coverts, the throat, and a nuchal collar, 

 white. 



The species inhabits the intertropical portions of both the Atlantic and 

 Pacific Oceans. 



In the shape of the bill, emargination of the tail, length of wing, and pe- 

 culiar proportions of the tarsus and toes, this species differs somewhat from 

 the other representatives of the genus Fregetta, as here adopted, so much so, 

 that ornithologists may perhaps hereafter find it expedient to restrict the genus 

 to this single type, and present the remaining species under a different ge- 

 neric appellation. 



2. Fregetta grallaria, Bp. ex Vieillot. 



This long known species has, in spite of its well marked characters, been 

 presented under so numerous and diverse designations, that its synonymy re- 

 quires careful consideration. 



The first unequivocal indication of this species that I have met with is that 

 given by Vieillot, on page 418 of vol. xxvi of the Nouveau Dictionnaire, (1817,) 

 under the name of '' Le petrel exhasse, Procellaria grallaria." The accompa- 

 nying description, though brief, is entirely pertinent to the present species ; 

 and Vieillot's name is, therefore, entitled to priority over subsequent desig- 

 nations. 



Prof. Lichtenstein has, in the Catalogue of the Duplicates of the Berlin 

 Museum, page 83, (1823), conferred the name grallaria upon a different species, 

 Yiz : the melanogastra of Gould. 



In 1820 ihe species was presented by Kuhl, Monogr. Proc, p. 138. pi. x. fig. 3, 

 under the name of" Procellaria /regatta, Banks." This author's description is 

 very full and quite accurate, but he erroneously adduces the name " P. xquorea" 

 as a synonym, whereas the latter really is a synonym of quite another species, 

 viz : the Procellaria marina of Latham. 



Bonaparte acknowledges, in his Conspectus, p. 198, the error he committed 

 in 1828, of referring to this species under the name of Thalassidroma oceanica, 

 he having in his synopsis of the Birds of North America confounded Vieillot's 

 grallaria with the Oceanites oceanica of this paper. 



Finally, in the Annals and Magazine of Natural History, Mr. Gould describes 

 this species as new under the name of Thalassidroma leucogastra. 



A tine suite of specimens are before me, among which are some of Mr. Gould's 

 typical examples, received by the Philadelphia Academy from him. They vary 

 more than is usual among the Procellaria, in the color of the upper parts, 

 which ranges from a deep fuliginous brownish black to a much lighter plum- 

 beous or ashen hue. Some the lightest colored ones have all the dorsal 

 feathers edged with greyish white. The circumocular region is usually the 

 darkest colored. The white of the under parts varies exceedingly in extent; 

 it sometimes reaches far up on the throat, including nearly all the under sur- 

 face of the bird ; while in other examples it is nearly as much restricted, that 

 is to say, descends as low on the breast as is usual in examples of melanogastra. 

 The lightest colored birds are apparently the most immature. 



The bill is stout, nearly as high as broad at the base, measuring from the 

 front to apex, about half the length of the skull. The nasal tubes are long and 

 elevated. The wings are moderately long, reaching just beyond the very 

 slightly emarginate tail. The second primary is longest ; the third nearly 

 equal ; the first iutermediate between the third and fourth. The rectrices are 

 exceedingly broad to their very tips, which are subtruncated. The tibiaj are 

 denuded fur the space of one inch. The tarsus measures 1-50 to 1-60 inches, 

 the middle toe and claw 1-05 to 1-10. The wing from the flexure measures 6 

 inches. 



The species inhabits the tropical portions of both oceans. 



[March, 



