IV. VERTEBRATA: AYES, CARINAT^E. 



(U5 



webbed feet, they are excellent swimmers and divers. Either all four toes 

 are connected by the web (totipalmate, fig. 643, Z), or only the three anterior 

 toes are webbed (palmate, fig. 643, k), or the three toes are each bordered 

 with a swimming membrane (lobate, fig. 643, h). Thus the foot struc- 

 ture gives distinctions which forbid a closer association of the families, and 

 this is strengthened by differences of wing and beak. On the other hand 

 palatal structures show that here, as in the Grallatores, very diverse forms- 

 are associated. 



Section I. LAMELLIROSTRES (Anseriformes), feet palmate; the beak soft- 

 skinned up to the hard tip, its margins with transverse horny plates. 

 Anas boschas* wild duck, source of domestic breeds. A. mollissima, eider; 

 Anser* goose (domestic derived from A. ferus). Cygnus* swans. Sec- 

 tion II. TUBINARES (Longipennes), predaceous birds with strong beak, 

 tubular nostrils, palmate feet, and long wings capable of rapid and pro- 

 longed flight. Diomedea, albatross; Larus,* gulls ; Sterna,* terns. Sec- 

 tion III. URINATORES. Birds with small wings, sometimes reduced to- 

 flippers, and upright position owing to position of the legs far back. The 

 ALCID^E (Alca impennis* the great auk, exterminated in the nineteenth 

 century), which are northern and are related to the gulls, and the antarctic 

 IMPENNES (Aptenodytes fig. 644, 

 penguin) agree in having palmate 

 feet, but otherwise differ greatly in 

 structure. Some of the COLYMBID.E 

 (Urinator* loons) have palmate 

 feet, others (Colymbus,* grebes) have 

 lobate feet. Section IV. STEGANO- 

 PODES, with totipalmate feet. Pele- 

 canus* pelicans; Phalarocorax,* 

 cormorants; Phaethon,* tropic birds. 



Sub Order IV. GRALLATORES. 

 The wading birds affect swampy 

 lands and the shores of the sea, 

 ponds and streams, their legs being 

 lengthened, chiefly by elongation of 

 the tarso-metatarsus, the feet semi- 

 palmate (fig. 643, a), and the feath- 

 ers only on the upper parts, the 

 lower with horny plates, all feat- 

 ures adapted to the wading life. FlG - && Aptenodyt.es patagonica, penguin. 

 Correlated is the striking length of (From Brehm -> 



neck and beak. These features have appeared in groups which are very 

 different in anatomical characters. 



Section I. CICONIFORMES. Beak with a strong horny coat. Ardea* 

 herons; Ibis ; Ciconia, storks ; Phcenicopterus,* flamingo. Section II. 

 GRUIFORMES. Beak always with soft skin at the base, often extending to 

 the tip. Grus,* cranes; Rallus* rails; Otis, bustards, terrestrial. Section 

 III. CHARADRIFORMES. Allied to the auks and gulls. Scolopax* woodcock ; 

 Charadrius,* plover. 



