GREAT SKUA. 
89 
The series in the Rritisli Museum varies from the typical 
Gull’s egg of clay-brovm with distinct overlying spots of dark 
brown and underlying spots of grey, to bluish-grey or creamy- 
buff, with the markings faint or very much emphasized. In 
the faintly-spotted eggs, the grey underlying spots are the most 
prominent, and in some instances the larger end of the egg is 
blotched with black. Axis, 2-2-2'35 inches; diam., 1-5- 17. 
THE SKUAS. FAMILY STERCORARIID/E. 
In structure the Skuas differ, markedly from the LaridcR, 
and their habits more resemble those of Frigate-Birds than 
Gulls, though some of the larger species of the last-named 
family are robbers by nature. These redeem tlieir character, 
however, by other milder traits, whereas the Skuas are among 
the most predatory of sea- fowl. They differ froui the Gulls 
and Terns in osteological characters, having only one notch 
in the posterior margin of the sternum, and the bill is 
furnished with a very elongated “cere,” and is formidably 
hooked, while the claws are more like those of a bird of prey 
than those of a sea-bird, being strongly curved and very sharp. 
Two genera are contained within this Family, both of which 
are represented in the British Avi-fauna, and are described 
below. 
THE GREAT SKUAS. GENUS MEGALESTRIS. 
Megalesiris, Bp. Cat. Parzud. p. ii (1856). 
Types, M. catarrhaclcs (Linn.). 
The members of the genus Megalesiris are four in number, 
one of them, M. catarrhactes, inhabiting the northern ocean, 
while another, AI. maccormickii, is only known from Victoria 
Land in the Antarctic Ocean. AI. chilensis inhabits the 
southern coasts of South America, and AI. aniarctica is found 
in the southern ocean from the Falkland Islands eastwards to 
New Zealand. The principal points of difference between the 
species of Alegalestris and Stercorarius consist in the larger 
bulk of the former and the shorter tail, the central feathers of 
which do not project more than half an inch beyond the rest, 
whereas in Sfercorarivs this prolongation of the middle tail- 
