249 
LARIDyE. 
The last family of the Natatores, typically repre- 
sented by the extensive group of tho Gulls, live in a 
manner by plunder. Some of the forms not by the 
exercise of their own exertions, but seize and carry 
off what has been watched for and procured by 
others; some, again, feed on the blubber of the 
larger cetaceous animals, the carrion, as it were, of 
the ocean ; and many of them, when slightly pressed 
by hunger, will avail themselves of very indiscrimi- 
nate food ; in most the bill is strong compared with 
the size, the wings long and ample ; while those 
that we shall describe first are the most exclusively 
sea-birds ; and, although they do not enjoy the 
property of diving, they seldom seek the land ex- 
cept while breeding. 
The British Petrels are comprised in three genera, 
two of which run very closely into each other. The 
birds are entirely maritime in their habits, and seem 
to run in zones of distribution ; the species are more 
numerous than what they are yet supposed to be, 
and present individuals very closely allied. 
Genus Proceharia, Linnceus Generic charac- 
ters . — Bill strong, straight, thick; maxilla di- 
