1 AMPHIBIOUS ANIMALS* 



infallibly prove fatal to most other orders of animals* 

 Several of the species have been known to exisf, 

 and in apparent health and vivacity, for many months 

 without food. 



They are able, from the peculiar structure of their 

 organs* to suspend respiration at pleasure ; and thus 

 to support a change of element uninjured. 



It is generally asserted, and believed, that the 

 hearts of the Amphibia are furnished with only one 

 ventricle : more accurate physiologists are, however, 

 of opinion that we ought rather to say that they 

 have two ventricles, with an immediate communi- 

 cation between 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 membranaceous receptacles, 

 parted into cancelli or small subdivisions, among 

 which are beautifully distributed their few pulmo- 

 nary blood-vessels. 



Many of the animals 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 pustular warts, or protube- 

 rances. — Their bones are more cartilaginous than 

 those either of quadrupeds or birds. Several of the 

 species are destitute of ribs. — Some are furnished 

 with formidable teeth, whilst others are entirely 

 without: some again are fierce and predacious ; and 

 others perfectly inoffensive. In general, however* 



