460 AVES. 



America. They are probably not a natural group,* but include forms which 

 properly belong to different tribes of the Carinatae. The principal genera 

 are Phororhacos, Brontornis, Stereornis, Patagornis, Dryornis. 



Sub-order 3. CARINATAE. 



This sub-order includes the great majority of birds. In the skull the 

 palatines and pterygoids articulate with the basisphenoidal rostrum at 

 the point where they join one another, and the head of the quadrate is 

 double or has two articular facets ; basipterygoid processes are present 

 or absent. The sternum is keeled except in the flightless forms (Didus, 

 Stringops, etc.). The coracoid and scapula meet at nearly a right angle. 

 The barbules carry hooks. 



Tribe 1. ICHTHYORNITHES. 



Extinct, toothed birds with amphicoelous vertebrae and well developed 

 wings ; the teeth are implanted in sockets ; from the Middle and Upper 

 Cretaceous of Kansas. Ichythornis Marsh, a bird of powerful flight ; 

 with teeth all along the lower jaw, but confined to the maxilla in the upper 

 jaw ; the head of the quadrate is single as in Ratitae and Odontolcae. A 

 pygostyle is present. 



Tribe 2. COLYMBIFORMES. Divers and grebes. 



Water-birds with webbed or lobed toes and flattened metatarsus. Body 

 carried upright, feet far back. Tail feathers short. Nestlings with com- 

 plete covering of down. Feathers with aftershaft. Aquintocubital. 

 Holorhinal with nares perviae. Schizognathous, without basipterygoid 

 processes. 



Fam. Colymbidae. Divers. Marine birds breeding on the shores of 

 inland waters, two eggs ; periarctic. Colymhus glacialis L., great northern 

 diver. 



Fam. Podicipedidae. Grebes. Body short, they construct nests of 

 water weeds ; the yoimg use their wings as fore-feet ; cosmopolitan ex- 

 cept in arctic and antarctic regions. Podicipes cristatus L., great crested 

 grebe. 



Tribe 3. SPHENISCIFORMES, Penguins. 



Flightless marine birds with anterior limbs covered with scalelike 

 feathers, without remiges, and used as paddles when the birds are sub- 

 merged ; plumage covering the whole body. The homy sheath of the 

 maxilla of from 3 to 5 pieces ; schizognathous, without basipterygoid pro- 

 cess ; nares imperviae ; bones of the anterior extremity strong, flattened ; 

 hallux without a web ; metatarsals united at their extremities only ; 

 feathers with or without barbs, with aftershaft ; with much subcutaneous 

 fat ; nests of grass or leaves in depression in the ground ; two eggs, both 

 sexes incubate ; yoiuig blind ; coasts of antarctic continent, southern 

 temperate zone, one tropical species (Galapagos). Aptenodytes patagonica 

 Forst., king -penguin (Fig. 252) ; Spheniscus demersus L., the Cape penguin ; 

 Eudyptes chrysocome L., Southern ocean, Falklands to New Zealand. 

 Fossil forms from the Eocene of New Zealand (Palaeeudyptes) and from 

 the Miocene of Patagonia (Paraptenodytea, etc.). 



