DUSKY PETREL. 663 



and to which it is so nearly allied, that assimilis appeared 

 to me to be the most appropriate specific appellation I 

 could apply to it. On my homeward voyage I saw nume- 

 rous examples flying off the north-eastern end of New 

 Zealand, and this, I regret to say, is all the information I 

 have to communicate respecting it." Two specimens of 

 this bird are in the collection at the British Museum, 

 presented by the late Sir Thomas Mitchell from Eastern 

 Australia, and the occurrence of this species at King 

 George's Sound, on the south-west coast, has been already 

 noticed. 



Birds of great and enduring powers of flight ; able, 

 moreover, to take their rest, and obtain their food on the 

 surface of the sea, may reasonably be expected to have a 

 wide geographical range; and of these powers the birds 

 belonging to the families of the Terns, Gulls, and Petrels 

 are good examples. 



The whole length of the bird, as previously mentioned, 

 is eleven inches ; bill to the feathers on the forehead one 

 inch ; the nail curved and shining black, the other parts 

 bluish-black ; the top and sides of the head, including the 

 eyes, the neck above, the back, upper tail-coverts, upper 

 surface of the tail-feathers, and the same parts of all the 

 wing-feathers ink black ; chin, sides of the head below 

 the eyes, throat, neck, breast, belly, under wing and tail- 

 coverts white ; on the sides of the neck, at the junction 

 of the dark and light colour, the feathers are barred 

 slightly ; axillary plumes white ; under surfaces of the 

 primaries blackish grey; darkest near the shaft of each 

 feather, becoming lighter in colour over the outer part of 

 each broad inner web ; under surface of tail-feathers uni- 

 form lead grey; legs, with the tarsal bones very much 

 compressed, blackish-grey, toes the same, the interdigital 

 membranes reddish-brown ; irides brown. 



