134 MANUAL 



nostrils are entirely separate and disconnected, and situate one 

 on either side the mandible. They are found usually far from 

 laud, and would seem to be sea-birds in the truest sense of the 

 word, seldom approaching land save for breeding purposes. 

 Two genera are known to North America. 



Genera, Diomedea, 2 species. 

 Phozbetria, 1 species. 



Phoebetria seems to be a proper genus, rather than a sub-genus, though 

 often occurring under the generic name of Diomedea. I know of no syno- 

 nyms : [Unless Thalassarche, which is a sort of sub-genus of Diomedea, 

 be one. It is used by Professor Baird as is the name Phoebastia — both 

 are used, however, rather as expressive of generic peculiarities than in a 

 sub-generic sense]. 



Sub-family b PROCELLARIN-S3 Petrels 



The True Petrels are known at once by the curious shape of 

 the nostrils, which have the appearance of a very short 

 double-barreled gun saddled to the base of the upper mandi- 

 ble. The general features of the Petrels are best studied, as 

 are many other of the bird groups, by means of a " typical " 

 specimen. Nearly all of the members of the group conform, 

 with slight variations in each genus, to this typical specimen 

 — and almost any one of the sub-okder will serve as typical. 

 Many families do not require this mode of study, a few do. 

 The shapes of the nostrils, of the wings and tail as modified 

 by the number of their feathers and the forked, even, or 

 wedge-like appearauce of the latter, size of both wings and 

 tail, and even the coloration of the various parts, all vary in 

 the different species and genera. 



Genera, Ossifraga, The Giant Fulmar. 



Fulmarus, The True Fulmar (3 species). 

 Priocella, The Slender-billed Fulmar. 

 Priojinus, Tbe Black-tailed Shearwater. 

 Pujfinus, The True Shearwaters (10 species). 

 (Estrelata, The Black-capped Petrel and ally. 

 Daption, The Cape Pigeon. 

 Halocyptena, The Least Petrel. 

 Procellaria, The Stormy Petrel. 

 Oceanites. Wilson's Petrel. 

 Cymochorea, Leach's Petrel and 2 allies. 

 Oceanodroma, The Forked-tailed Petrel (2 species). 

 Fregeita, The White-bellied Petrel. 



