BIRDS—GAVIAE 
819 
Procellaridae. —Nail only of hind toe projecting. Nasal apertures circular, opening 
in projecting tubes. Bill with a much decurved nail at tip. Outer toe as long as the 
middle. Legs reticulated in front. 
Laridae. —Hind toe free when present. Nasal apertures linear, opening laterally ; not 
at all tubular. Bill without nail except in Lestris. Outer toe shorter than the middle. 
Legs scutellate transversely in front. 
C. Brachypteri. —Wings and tail short, the latter sometimes wanting. Hind toe free, or 
wanting. Legs very far backwards. Entirely aquatic, and for the most part capturing the 
food beneath the water. 
Colymbidae. —Hind toe distinct, with a broad hanging lobe. The membrane of toes 
entire, or divided. Claws nail-like, flattened. Mostly inhabit fresh waters of all 
countries. 
Alcidae. —Hind toe wanting. Claws compressed. Entirely marine, and chiefly arctic. 
In a strictly natural arrangement the Totipalmi should, perhaps, precede the Longipennes. 
In order, however, to facilitate the passage of the present report through the press, the latter 
tribe has been made to begin the sub-order, as the manuscript belonging to it was first ready for 
the printer. For a similar reason the Anseres come before the Gaviae, although most authors 
place them last. 
The determinations and descriptions of the Gaviae have been prepared and furnished by 
Mr. George N. Lawrence, with the exception of the Alcidae , which are from the pen of 
Mr. John Cassin. 
