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 Carinate 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 Lamellirostret. 



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; 



tibia? often spurred GalUnce. 



7. Toes like the foregoing; the bill horny and convex 



at tip ColumbcB. 



8. Bill cered, hooked, and large; feet large, not yoke- 



toed Raptores. 



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 Picarice. 



11. Perching and singing birds; feet adapted for 



grasping; hind toe opposed to the others Passeres. 



Sub-Class I. — Carinate. 



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 other birds; 

 the wings are small, paddle-like, with scale-like feathers; 



