404 NATATORES. COLYMBUS. 
greenish-black, inside livid, and tinged with flesh-red. 
Asperities on the hinder edge of the tarsus prominent, 
and sharp-pointed. Head, chin and throat, nape and 
back part of the neck, glossy black, with a slight tinge 
of green. Auriculars, sides of the neck, and middle of 
the fore part of the neck, rich orange-brown. Breast, 
sides and flanks, glossy blackish-grey, the latter having 
the lower parts of the feathers and the down pale red- 
dish-brown. The rest of the under plumage silky 
white, intermixed with blackish-grey. Upper plumage 
glossy black, tinged with oil-green. Secondary quills 
having their bases, and the greater part of the webs, 
white. 
Fig. 2. Represents the immature bird, destitute of the 
orange-brown upon the neck, and having the chin white. 
The upper plumage is also lighter in colour, and the 
belly and abdomen are pure white. 
Genus COLYMBUS, Lary. DIVER. 
GENERIC CHARACTERS. 
Bitt rather longer than the head, strong, strait, com- 
pressed, and sharp pointed ; the upper mandible slightly ex- 
ceeding the lower one in length. 'Tomia of both mandibles 
bent inwards and sharp. Nostrils basal, lateral, linear, ob- 
long, pervious, half closed by a membrane. 
Wings short, acuminate, having the first quill-feather the 
longest. Tail short and rounded. 
Legs abdominal, or placed at the further extremity of the 
body, with the tibize concealed within the integument. Tarsi 
thin, very much compressed. Feet large, of four toes, three 
before and one behind; outer toe exceeding the middle one 
