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CLASS IIL AMPHIBIA. 



.Remarks. The blood of animals is rendered 

 warm and capable of exciting nervous action 

 by the process of respiration. Amphibious ani- 

 mals have their circulatory system so arranged,, 

 that but a part of the blood passes into the lungs ; 

 consequently does not receive the benefit of free 

 respiration. The necessary deficiency in the 

 warmth and in the exciting power of the blood, 

 predisposes them to a torpid state. And though 

 some of them move with rapidity at times ; they 

 are generally torpid, their digestion slow, their 

 senses dull, and some of them pass the winter in 

 a lethargic state. Even if the head is separated 

 from the body, life is still manifested by muscular 

 action for a long time. Their pulmonary vessels 

 are so small, and respiration so slow, that they 

 may remain long under water without producing 

 any change in the circulation of the blood. 



ORDER 1. CIIELONIA. 



Having a covering consisting of a shell on the 

 back and on the breast, and walking or swimming 

 frith four feet. Heart with two auricles. 



TESTUDO, (tortoise,) body defended by a bony 

 covering, or coated by a horny, scaly or coriaceous 

 integument ; mouth with a sort of serrate mandi- 

 bles, and not proper teeth ; the upper mandible 

 closing over the lower. 



