CLASSES. 39 



feet. They feed chiefly upon living animals. 

 They do not pass through any material change 

 after they are produced,, as insects do. 

 Examples. Spider, grey-heard. 



8. INSECTA, animals with jointed limbs, and an- 

 tente. They respire by two principal trachea or 

 pipes running parallel to each other through the 

 whole body ; which throw off at intervals many 

 branches to the surface of the body, through which 

 air is admitted. 



The head and thorax are distinct, antennae two. 

 They are mostly winged, having one or two pair : 

 a few are without wings. They have six feet, 

 excepting thai some of the wingless genera have 

 more : their mouths consist of six pieces, dispos- 

 ed in pairs, but do not all move in the same direction. 

 One pair is sometimes called the mouth or mandi- 

 bles, another the lips, another is a kind of cloven 

 tongue. In some insects the mandibles become a 

 kind of beak. Most insects pass through several 

 states of transmigration. 1. The egg, 2. the lar- 

 va, 3. the chrysalis, 4. the perfect insect 



Example. Thousand-leg, flea, grasshopper, 

 butterfly, miller, house-fly. 



MOLLUSCOUS ANIMALS 



ARE INCLUDED IN ONE* CLASS. 



9. MOLLUSC. \, bodies soft without internal skele- 

 ton, external crust or jointed limbs. Covering, a 

 soft skin -without rings ; sometimes defended by 

 stony plates. 



Blood white or bluish. Their muscles being 

 attached to the skin without any solid supporters ; 



* Cuvier divides them into six classes. But it appears to be more 

 convenient to make orders of such obscure classes. 



