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TAXONOMY 



amphibians undergo a complete metamorphosis. The larval form 

 comes from an egg, lives in the water, and possesses gills. Frogs. 

 Class V — Reptilia. Cold-blooded vertebrates usually cov- 

 ered with scales, breathing throughout life by means of lungs. 

 The heart is three-chambered. Lizards, snakes, and turtles. 



Class VI — Aves. Thehirds. Warm-blooded vertebrates cov- 

 ered with feathers. Front limbs are wings ; they have air spaces 

 in the bones, no diaphragm, and a four-chambered heart. Birds 

 lay eggs with a shell of lime, and usually care for their young. 

 Class VII — Mammalia. Warm-blooded animals covered 

 with hair, at some stage. Usually have mammary glands and 

 suckle the young. They have a diaphragm between the thorax 

 and abdomen. This class may be divided into eleven orders : 

 Order 1 — monotremata. Egg-laying mammals. Duck- 

 bill, spiny anteater. 



Order 2 — marsupialia. Carry immature young in a 

 special abdominal pouch. Kangaroo, wombat, opossum. 



.V. Y. Zoological Society 



Darwin did not say that man came from monkeys. He and other evolutionists believe that 

 there is a common ancestor of man and certain of the apes. 



Order 3 — Edentata. Toothless or with very simple teeth. 

 Hairy anteater, sloth, armadillo. 



