NATATORES. 443 



As will be seen, the ten following species of Petrels have 

 been divided into several genera, the majority of which have 

 been adopted by Dr. Elliott Coues in his valuable memoirs on 

 this family of birds in the * Proceedings of the Academy of 

 Sciences of Philadelphia' for 1864. Generally speaking, all 

 of them are of medium size, the exception being the Ossifraga 

 gigantea, jEstrelata leucojjtera, and JE. cooki, which, on the 

 one hand, leads to the Albatroses, and on the other, through 

 HalobcB7ia, to the more diminutive Prions. 



Genus OSSIFRAGA, Homh. et Jacq. 



Of this genus but one species is known. It is a most 

 powerful bird, equalling in size and strength the smaller 

 Albatroses. The sexes are alike in plumage. 



Sp.624. OSSIFRAGA GIGANTEA. 



Giant Petrel. 



Procellaria gigantea, Gmel. Edit, of Liun. Syst. Nat., vol. i. p. 563. 



ossifraga, Forst. 



Mother Gary's Goose, Cook's Voy., vol. ii. p. 205. 

 Giant Petrel, Lath. Gen. Syn.^ vol. vi. p. 396, pi. 100. 

 Ossifraga gigantea, Bonap. Compt. Rend, de PAcad. Sci., 1856. 



Procellaria gigantea, Gould, Birds of Australia, foL, vol vii. pi. 45. 



This, the largest of the Petrels, is universally distributed 

 over all the temperate and high southern latitudes : and that 

 it frequently performs the circuit of the globe may, I think, 

 be fairly inferred from the circumstance of an albino variety 

 having followed the vessel in which I made my passage to 

 Australia for three weeks while we were running down our 

 longitude between the Cape of Good Hope and Tasmania, the 

 ship often making nearly two hundred miles during the 

 twenty-four hours ; it must not, however, be understood that 

 the bird was merely following the vessel's speed, nor deemed 



