Petrels from the Nortli-East Pacific Ocean. 591 



We consider edivards Oustalet a subspecies of kii/i/l, 

 yetJcouun Acerbi a subspecies of pvffinus, subalaris Ridgvvay 

 and audaboni Finsch subspecies of Iherminieri, and elegans 

 G. & S. and bailloni Bp. subspecies of assimilis Gould. 



The relations of the genera seem to be ill-defined : Calo- 

 nectris and Ardenna stand quite apart from all the rest with 

 regard to size and form and to some extent coloration also ; 

 while though the lateral compression of the tarsus of species 

 of Ardenna is as much as in any other member of the group, 

 and this lateral compression of the tarsus is almost a 

 supergeneric character, Calonectrts differs in this feature. 

 Consequently we cannot state that these two genera are as 

 closely allied as a superficial examination suggests. Neither 

 would we be justified in allving them to any other genus. 

 There is a huge gap between them and Puffinus, and they 

 approach Proceltaria {■= Majaqueus) more nearly. Perhaps 

 they are nearest to Priofinus, which they resemble closely in 

 coloration and with which genus the species have sometimes 

 been confounded. In considering this genus we have noted 

 that Cones observed that it was very close to Pu^nus, and 

 Mathews went so far as to lump it with Procellaria, noting 

 it only differed in coloration. Procellaria is, so far as at 

 present known, a Puffinoid form, but it is wholly black and 

 does not show the supergeneric character of the peculiar 

 coloration of the legs and feet. We now see that Priofnus 

 does show this character, and that therefore it must be 

 placed alongside Ardenna. Still, this does not help us with 

 the affinities of the species, but only adds another problem. 



Pvffinus s. str. is homogeneous, and we trace it into 

 Reinholdia, which differs in the very diminished tail, and 

 into Alphapu^nus, which contains the smallest members of the 

 group with small bills but average tails. We are here again 

 at a loss as, unless we work through the species cuneaius, we 

 cannot account for the dark long-tailed Thyellodroma. All 

 the species of Pirffinus, save nativitatis Streets, Reinholdia 

 and Alphapvffitius are bicolor ; while in Thyellodroma, 

 cuneata and bul/eri are bicolor, the former perhaps di- 

 morphic, and pacificus unicolor. Contrasted with these 



