retreh from the North-East Pacific Ocean. 597 



new subgeneric name and tlius attract attention to it. A\ e 

 would tberefore propose 



Sub-genus MiCRozALiAs, nov. 



for Puffinus nativitatis Streets. 



The genus Thyelludroma is composed of bicolor and 

 unicolor species, and these are large, but not the largest, 

 pufiinoid birds with long wedge-tails. Whether there are 

 two or three species is not yet decided, and though Mathews 

 regarded two only as specifically distinct, we here revert to 

 the treatment in the ' Monograph,' where three were 

 admitted. 



The genus covers the only case in the puffinoid group 

 where dimorphism or interbreeding is suggested, and pro- 

 bably later information will once more radically change our 

 conclusions. 



Thyellodroma cnneata cuneata (Salvin). 



Puffinus cuneuius Salvia, Ibis, 1888, p. 353 ; Krusenstern 

 Island, Marshall Group. 



This species was described from a couple of skins from 

 the Marshall Group, and the further history of its discovery 

 is retailed in the ' Monograph,' p. 7Q. In the ' Birds of 

 Australia,' vol, i. 1912, pp„ 82-84, Mathews discussed the 

 phases and lumped all the birds previously named Pufflims 

 cuneatus under Pvffinus pacificus, distinguishing several 

 subspecies. In the present collection six specimens occur, 

 and a re-investigation of the group was necessary. We now 

 differentiate two species, T. cuneata and T. pacifica, and note 

 that the subspecies as regards general coloration are constant 

 save in two localities. 



An example from Owston's collection is labelled as 

 follows : — 



" Bonin Is., May 1910. Pvffinus cuneatus Salv." 



Culmen 41, wing 280, tail 137-5, tarsus 47, mid-toe 48 mm. 



General coloration above brownish ; below pure white with 

 a slight freckling of grey on sides of body ; under tail- 

 coverts brown. Compared with the type of Pufiuus cuneatus 



