with descriptions of new species. 367 



line. It is the largest member of the genus with which I am ac- 

 quainted, and is rendered very conspicuous by the white mark 

 on its throat. 



Thalassidroma marina, Less, — Very common in all the Austra- 

 lian seas. The specimens in my possession were found breeding 

 and procm'ed on the islands near Augusta, on the western coast 

 of Australia. 



Thalassidroma Wilsoni, Bonap. — After a careful examination 

 of numerous specimens fi'om the xVustralian seas with others taken 

 in the North Atlantic, I cannot come to any other conclusion than 

 that they are identical ; an anomalous fact, since it is the only 

 species with which I am acquamted that fi'equents the seas on 

 both sides of the equator. 



I met with it in considerable numbers in Basses Straits, and 

 observed it in every degree of temperate latitude. 



Thalassidroma Nereis, Gould, Proc. of Zool. Soc. part 8. p. 178. 

 — I have never seen this highly interesting species in any other 

 parts of the ocean than Basses Straits and the seas washing the 

 southern shores of Australia. 



Thalassidroma melanog aster, n. sp. — All the plumage deep 

 sooty black, with the exception of the upper tail-coverts and 

 flanks, which are snow-white ; bill, legs and feet black. 



Total length 1~ inches ; bill | ; mng 6 ; tail 3 ; tarsi \^ ; mid- 

 dle toe and nail 1^. 



This species is very abundant in the South Pacific and Indian 

 oceans, particularly off the islands of St. Paul's and Amsterdam. 

 I also met with it midway between those islands and Van Die- 

 men's Land. It is a species which cannot be mistaken at sea, 

 from the black mark which occupies the centre of the abdomen, 

 and contrasts so strongly with the white flanks. 



Thalassidroma leucogaster, n. sp. — Head and neck deep sooty 

 black ; back grayish black, each feather margined with white ; 

 wings and tail black ; chest and all the under surface and upper 

 tail-coverts pure white ; bill and feet jet-black. 



Total length 7:^ inches; bill ^; wing 6; tail 3; tarsi li; mid- 

 dle toe and nail 1. 



This bird was killed in 36^ S. lat., 6° 47' E. long., by His Ex- 

 cellency Governor Grey. 



I have a small petrel presented to me by Mr. Denison, who 

 killed it near the coast of Australia on his passage to Sydney, 

 in which the nostril-tube is much more lengthened than in any 

 other species, and its apical portion turned upwards or recurved 

 instead of being attached to the bill throughout its entire leneth 

 as in the other members of the genus. In the distribution of its 

 colouring it is very nearly allied to T. tropica and T. leucogaster, 

 and it may be a mere variety of one or other of those species • 



