v ALCIDAE 315 
and feet red, and a white streak marking each cheek. In the 
winter and immature plumage the under parts are entirely, and 
the head partially white, throughout the genus. 
Of fossil Laridae Halcyornis occurs in the Lower Eocene of 
England, Aegialornis' in the Upper Eocene of France; while 
the Lower Miocene of the latter country, the Middle Miocene 
of Germany, and the Phocene of Oregon furnish Larus. 
Fam. VIII. Alcidae.—The Sub-order ALCAE contains only 
this Family, or the Auks, wherein the body is heavy and compact, 
the head large, the plumage close and elastic. The stout bill 
varies extraordinarily, as will be seen under the various species. 
The abbreviated metatarsus is reticulated, usually with a row of 
scutellae in front; the long anterior toes are fully webbed, the 
hallux is absent or rudimentary, the claws are stout, acute, and 
slightly curved. The wings are very short, and the Great Auk 
was absolutely flightless ; but most species fly strongly and rapidly 
to varying distances, the pinions not being flipper-like as in the 
Penguins, to which these birds have no affinity; like them, however, 
they commonly sit upright upon the metatarsus, and walk awk- 
wardly from the feet being placed so far back, while they swim and 
dive to perfection. The primaries are eleven, the secondaries from 
fifteen to nineteen. The short tail may be rounded as in Uva, 
or graduated with pointed rectrices as in Alcea; the quills num- 
bering twelve, except in A. impennis, which has eighteen. The 
furcula is U-shaped, the syrinx tracheo-bronchial, the tongue 
lanceolate ; the nostrils—covered with feathers in Alcea, Uria and 
Mergulus, and with a horny membrane elsewhere—are pervious. 
An aftershaft is present, and down is plentiful on both adults and 
nestlings, being in the latter fluffy, and of a black, grey, or 
brown colour, sometimes relieved by white. Elongated feathers, 
crests, and horny outgrowths are common, as described below. 
Auks are entirely pelagic birds, breeding from the Polar Seas 
southwards to Japan, Lower California, Maine, and the Berlengas 
off the Tagus, while wandering further in winter; but the North 
Pacific may certainly be considered their headquarters. In the 
case of the British species a small proportion remain near shore 
after the autumn, but it seems to be quite uncertain where the 
majority spend the colder months. The members of this Family 
ean hardly be called gregarious, except in the breeding time, 
1 Since referred by Milne-Edwards to the Cypselidae as Tachyornis. 
