348 



CLASSIFICATION OF VERTEBRATES. 



and in most cases, as in the ducks (Anas}, geese (Anser}, swans (Cygnns), 

 and flamingoes (P he nicop terns), webbed and fitted for swimming, while 

 in the screamers (Anhima) the web is lacking. The young when hatched 

 are feathered, and able to feed themselves. The HERODII includes 

 altrical forms (p. 330), in which the legs are very long, the toes, of which 

 three are directed forwards, are usually without webs, and these birds, 

 like the grallae of the schizognathous section, are wading forms. The 

 various species of Ibis, the spoonbills (Platalea), storks (Ciconia), herons 

 (Ardea, Herodias}, and bitterns (Botaurus}, are familiar examples. The 

 ACCIPITRES (Raptores) are recognized by their hooked bill and claws, the 



toes, three of which are di- 

 rected forwards, being with- 

 out webs. There is no ba- 

 sipterygoid process, and the 

 young are altrical in char- 

 acter. The hooked beak 

 is shared by the parrots, 

 but the toes at once dis- 

 tinguish the two groups. 

 The birds of prey include 

 the vultures and buzzards 

 (Cathartes, Gyps, Sarcor- 

 ]ianip li n s) , the eagles 

 (Aquild), hawks (Bnteo. Ac- 

 cipiter}, and falcons (Falco], 

 forms which are closely alike 

 in structure and differ con- 

 FIG. 340. Wood-duck, Aix sponsa, from siderably from the nocturnal 



Tenney, after Audubon. owls x (Sfrt.i; Bubo, Scops, 



etc.), which compose the rest 



of the family. The COCCYGOMORPH^E, as a rule, have three toes directed 

 forwards, but in the cuckoos and toucans the first and fourth toes are 

 turned backwards, while in the colics (Coitus') all four toes are directed 

 forwards. In all the rostrum is movable. Typical genera are the plan- 

 tain-eaters (Musophaga), the cuckoos (Cuculus, Geococcyx), the night-hawks 

 (Caprimulga, Chordediles), the rollers (Coracias), bee-eaters (Merops\ 

 motmots (Momotus}, todies (Todns), kingfishers (Halcyon and Alcedo], 

 the hornbills (Buceros), hoopoes (Upupa), puff birds (Monasa, Bucco}, tou- 

 cans (Rhamphastos), and honey guides (Indicator'). The TROGOMIU-: 

 are characterized by having toes one and two directed backwards. The 

 STEATORNITHID/E resemble the rollers in many of their characters, but 

 they differ from them, as from all desmognaths except the parrots, in 

 the opisthocoele character of the vertebrae. Three toes are directed 

 forward. The oilbird (Steatornis caripensis) of South America is the 

 1 The owls may be more nearly related to Coracias than to the Accipitres. 



