NATURALIST'S CABINET. 



Capable of enduring long abstinence. 



most probably, stationed to prevent the excessive 

 multiplication of water animals and insects ; and 

 themselves, in many instances, to serve as food 

 for birds- and fish. They do not chew their food, 

 but swallow it whole, the throat and stomach 

 being capable of great distention, sometimes re- 

 ceiving animals of greater thickness than them- 

 selves in a natural state. Some, but not many 

 of them, live on plants or flesh. They have a 

 power of enduring abstinence that would infalli- 

 bly prove fatal to most other orders of animals. 

 Several of the species have been known to exist, 

 and be in apparent health and vivacity, for many 

 irlonths without food. Many assert that the 

 hearts of the amphibia are furnished with only 

 one ventricle ; but more accurate physiologists 

 are, however, of opinion that they have two ven- 

 tricles, with an immediate communication be- 

 tween them. The blood is red, but cold, and in 

 small quantity. The lungs consist, for the most 

 part, of a pair of large bladders or membrana- 

 ceous receptacles, parted into cancelli or small 

 subdivisions, among which are beautifully distri- 

 buted their few pulmonary blood vessels. 



These animals in general possess a high degree 

 of reproductive power, and when their feet, tail, 

 &c. are by any accident destroyed, others will 

 grow in their place. Their bodies are sometimes 

 defended by a hard horny shield or covering, 

 and sometimes by a coriaceous integument; 

 some species have scales, and others soft pustu- 



