448 BRITISH BIRDS. 



Genus OCEANITES. 



When Wilson's Petrel was first described by Kuhl in 1820, he placed it 

 in the genus Procellaria, and in 1834 it was removed by Nuttall to the 

 genus Thalassidroma but the two genera being synonymous, in 1840, 

 Keyserling and Blasius, in their ' Wirbelthiere Europa's/ page 238, estab- 

 lished the genus Oceanites for Wilson's Petrel, making it the type. 



The Petrels belonging to this genus are so precisely similar to the typical 

 Petrels, that a superficial observer would regard them as congeneric, 

 nevertheless a recent morphologist has placed them in different families. 

 Probably Forbes placed far too high a classificatory value on the characters 

 of the muscles ; but there can be no doubt that Wilson's Petrel belongs to 

 a group of very highly specialized birds, which may be distinguished not 

 only from all other Petrels, but from all other water-birds, by having the 

 tarsus booted or plated, instead of being covered with small reticulations 

 or slightly larger scutellations. The tarsus is slightly longer than in the 

 true Petrels, but in other respects no important external characters present 

 themselves. 



There are several species belonging to this genus, all confined during the 

 breeding-season to the Southern Seas. One only is an accidental visitor 

 to Europe. 



In their habits and nidification they precisely resemble their allies. 



