210 
ZOOLOGY. 
take turns in sitting on them. The nest may be left un- 
covered during the heat of the day, but in this region 
(Buenos Ayres), I believe, it is never entirely deserted. 
[American Naturalist, July, 1883.) 
Orders of Carina te Birds. 
1. Wings small and short; diving birds Pygopodes. 
2. Wings long, pointed; rapid fliers; anterior toes 
webbed. Longipennes. 
3. Feet wholly webbed, including the inner toe Stegopodes. 
4. Bill lamellate, i.e., both mandibles with teeth-like 
projections Lamelliros^treH. 
5. Wading birds; the leg long and naked above the 
heel; bill usually long and slender Grallatores. 
6. Land birds; four toes, three in front, one behind; 
tibiae often spurred » GalUnm. 
7. Toes like the foregoing; the bill horny and convex 
at tip Columhce. 
8. Bill cered, hooked, and large; feet large, not yoke- 
toed Bapiores. 
9. Feet yoke-toed; bill stout, and strongly hooked. . .Psittaci. 
10. Toes often in pairs, two in front and two behind; 
wings with ten primaries Picarim. 
11. Perching and singing birds; feet adapted for 
grasping; hind toe opposed to the others Passeres. 
Sub-Class L — Cari^^-at^. 
General Characters of Carinate Birds. — All other living 
birds belong to this group; they are remarkably homogene- 
ous in form and structure. They are characterized by the 
keeled breast-bone or sternum — the wings, as a rule, being 
well developed. 
Order 1. Pygopodes (Diving birds). — These are eminent 
as swimmers, and comprise the penguins, auks, puffins, 
grebes, and loons. The penguins (Figs. 246, 247) are con- 
fined to the antarctic regions. They are large birds, and 
form a characteristic element in a Patagonian landscape. 
The bones are solid, not light and hollow, as in otlier birds; 
the wings are small, paddle-like, with scale-like feathers; 
