98 Dr Fleming cm the Arctic and Skua Gulh, 
other gulls. This character, viewed in connection with its pre- 
datory habits, has procured for the largest species the name of 
Sea Eagle. 
The feathers of these birds have a very strong smell, not un- 
like those belonging to the petrels. 
There is no difference of plumage between the sexes. The 
young birds more nearly resemble the adult ones in the colour of 
their plumage than those pertaining to the species of true gulls. 
With characters so very different from the true gulls, it is 
necessary to consider these as constituting a distinct genus, 
Willoughby, in his Ornithologia, p. 22, when enumerating the 
British birds, places the Cataractes, the species which has been 
longest known to naturalists, as a genus distinct from the gulls 
and terns. In the body of his work, however, p. 265, he in- 
serts it in the section of the larger gulls, of a brown or grey co- 
lour. Brisson, in his Ormthologie, afterwards adopted the same 
genus, under the denomination Stercoraire. Buffon named it 
Lahhe ; and more recently Illiger has termed it Lestris. 
As Willoughby was the first ornithologist who gave an accu- 
rate description of any of the species, and indicated the propriety 
of placing the one known to him in a genus apart from the 
gulls ; the name which he imposed ought to obtain the prefer- 
ence. It is derived from the Greek word a cataract, 
and alludes to the velocity with which these birds descend 
through the air upon the objects of their pursuit. The bird to 
which Aristotle applied this name cannot now be identified, as 
his description is both short and obscure. 
The following may be considered as the systematical charac- 
ter of the genus Cataractes or Skua, by which it may be dis- 
tinguished from the genus Larus. 
Bill strong and straight. The upper mandible hooked at the end ; 
the margin of the under mandible sloping downwards at the apex. 
Nostrils linear ; rather widest in front; pervious^ situated near the 
middle of the mandible, and covered with a corneous plate reach- 
ing to the feathers at the base. 
Tongue bluntly bifid. 
Claw of the inner toe arched. The back toe distinct. 
The Skuas resemble the gulls and terns, in confining their 
operations to the surface of the water. Like them the body is so 
thickly covered with feathers, and so light in proportion to the 
