NORTH AMERICAN 



HERPETOLOGY 



INTRODUCTION. 



Reptiles form the third great class of vertebrated animals. They are beings 

 provided with lungs, a simple heart, low temperature, slow digestion, and 

 oviparous generation; having neither hair, feathers, nor mammfB. 



Naturalists have experienced much difficulty in giving an appropriate name to 

 this great class of animals. Linnajus, observing some of the most remarkable 

 phenomena in the economy of Reptiles — as their being able to live on land or in 

 water — called them amphibia. The term is inappropriate; for it can be applied 

 but to a very small number; as many never approach the water, and few, like the 

 Sirens, can respire in this clement; — breathing with lungs, others must approach 

 its surface for atmospheric air. The respiration of young Batrachia is indeed 

 only in water; but they have gills, and when the animal arrives at its perfect state 

 of development, these disappear, and are succeeded by lungs. An animal, to 

 respire equally well on land or in water, must have both gills and lungs; gills to 

 l)reathe in the water, as Fishes, and lungs to respire atmospheric air, as Birds 

 and Mammalia. The Sirens of our rice-fields, and the Menobranchi of the great 

 northern lakes, arc the only North American Reptiles that have this structure; 

 Vol. I.— 3 



