NATURAL SCIENCES OF PHILADELPHIA. 87 



3. Fregetta melanogastra, Bp. ex Gould. 



Thalassidroma melanogastra, Gould, Ann. et Mag. Nat. Hist., xiii. p. 36V. 



I have had an opportunity of examining Mr. Gould's typical specimens of 

 this species, now in the collection of the Philadelphia Academy. Although it 

 is very closely allied to the preceding, both in form and colors, yet it con- 

 stantly differs as follows : While a somewhat smaller bird, it has yet consid- 

 erably longer tarsi and toes ; the bill is longer, slenderer, with a more atten- 

 uated and gradually decurved unguis. The wing is nearly an inch shorter ; 

 the proportions of the primaries about the same as in grallaria. The tail 

 is about a third of an inch less. With the same general distribution of colors 

 as in ffrallaria, this species differs in the presence of a central longitudinal brown- 

 ish black streak, which divides the white of the abdomen into two symmetrical 

 lateral halves. This ray is not always perfect, being sometimes only indicated 

 by a few disconnected, black feathers. I have never, however, in a large num- 

 ber of specimens seen it entirely wanting, but even if this be ever the case, the 

 species may be readily diagnosed by its peculiarities of size and form above 

 detailed. 



The species inhabits the tropical regions of the Pacific Ocean. 



This is, in all probability, the species indicated by Forster, Descriptiones 

 Animalium, Edit. Lichten^tein, 1844, p. 180, under the name of " Procellaria 

 fregata, Linn. ;" at least, I judge this to be the case (although no mention is 

 made of the ventral ray) from the annexed foot-note, by Prof. Lichtenstein, in 

 which the latter says that it is upon this species (fregata, Forst.) he has based 

 his Procellaria grallaria, (Cat. Dupl. Berl. Mus. p. 83) which is " ob longitudi- 

 nem pedum segreganda." This length of the feet is exactly the most patent 

 point of difference in form of this species from the preceding. 



4. Fregetta Lawrencii, Bp. ex Lawr. 



Thallassidroma fregetta, Lawrence, Annals of the New York Lyceum of Natu- 

 ral History, 1851, p. 117. Fregetta Lawrencii, Bonaparte, Conspectus Avium. 

 ii. p. 198. 



It is exceedingly to be regretted that the typical and only known specimen 

 of this species has been lost, so that there is no opportunity of comparing it 

 with leucogastra, to which it is so very closely allied. I can, therefore, do no 

 more than simply present Mr. Lawrence's description, from which ornithologists 

 must judge for themselves regarding its specific validity. 



" Head and wings black ; neck, breast and back dark plumbeous, or dull 

 bluish ash ; wing coverts brown; the tail white at the base, with the terminal 

 half and the two central feathers black; abdomen, inside of wings and rump, 

 white ; bill and legs black. Tail even ; claws flattened and of an ovate form. 

 Length about 8 inches ; wing 6 ; tail 3 ; tarsus If. (Gen. Rep. Birds N. A., 

 p. 832). 



I VII. PELAGODROMA, Reichenbach. 



A very peculiar genus of Procellarieae, readily recognizable by the following 

 characters : 



Bill very long, but little less than the head, exceedingly slender, much com- 

 pressed, higher than broad at the base, the nasal tubes very short, less than 

 half the culmen, the unguis attenuated only slightly and very gradually de- 

 curved. Wings of moderate length, reaching just beyond the tail; second 

 primary longest, third nearly equal, first about equal to the fourth. Tail very 

 long, nearly square or but slightly emarginated, the feathers all exceedingly 

 broad to their truncated apices. Legs very long, somewhat stout, only mod- 

 erately compressed. Tibiae denuded for an inch or more. Tarsus of ordinary 

 length for this group ; toes all unusually long, the middle with its claw being 

 but little less than the tarsus. Iuterdigital membranes all very full and broad. 

 Of large size, rather stout form, and variegated colors. 



This genus agrees with Fregetta in many respects, but differs markedly from 



1864.] 



