THE VERTEBRATE ANIMALS 311 



had not only wings and feathers, but also teeth and a lizardlike tail. 

 From these fossil remains and certain structures (as scales) and habits 

 (as the egg-laying habits), naturalists have concluded that birds and rep- 

 tiles in distant times were nearly related and that our existing birds 

 probably developed from a reptile-like ancestor millions of years ago. 



CLASSIFICATION OF BIRDS 



DIVISION I. Ratite. Running birds with no keeled breastbone. Examples! 



ostrich, cassowary. 

 DIVISION II. Carinatce. Birds with keeled breastbone. 



ORDER i. Passeres. Perching birds ; three toes hi front, one behind. One half 

 of all species of birds are included in this order. Examples : sparrow, thrush, 

 swallow. 



ORDER n. Gallince. Strong legs ; feet adapted to perching. Beak stout. Ex- 

 amples : jungle fowl, grouse, quail, domestic fowl. 



ORDER in. Raptores. Birds of prey. Hooked beak. Strong claws. Examples : 

 eagle, hawk, owl. 



ORDER iv. Grallatores. Waders. Long neck, beak, and legs. Examples: snipe, 

 crane, heron. 



ORDER v. Natatores. Divers and swimmers. Legs short, toes webbed. Ex- 

 amples : gull, duck, albatross. 



ORDER vi. Columbce. Like Gallinae, but with weaker legs. Examples : dove, 

 pigeon. 



ORDER vn. Picarics. Woodpeckers. Two toes point forward, two backward, 

 and adaptation for climbing. Long, strong bill. 



REFERENCE BOOKS 

 ELEMENTARY 



Walker, Our Birds and their Nestlings. American Book Company. 

 Beebe, The Bird. Henry Holt and Company. 



Nature Study Leaflets, XXII, XXIII, XXIV, XXV, Cornell Nature Study Bulle- 

 tins. 

 Walter, H. E. and H. A., Wild Birds in City Parks. 



ADVANCED 



Apgar, Birds of the United States. American Book Company. 



Bulletins of U.S. Department of Agriculture, Division of Biological Survey, Nos. 1, 



6, 15, 17. See also Yearbook, 1899, etc. 

 Chapman, Bird Life. D. Appleton and Company. 

 Riverside Natural History,Vol. IV. Houghton, Mifflin, and Company. 



Mammals 



Mammals. Dogs and cats, sheep and pigs, horses and cows, 

 all of our domestic animals (and man himself), have characters of 

 structure which cause them to be classed as the type of vertebrate 



