■^ 



6 BUFONIDEA. 



of evening, and are truly nocturnal in their mode of life. This family has been 

 arranged in several genera, characterized by the form and structure of the tongue; 

 the number of toes, palmated or not; tympanum visible or not; tubercle at heel, 

 &c. &c. Two of these genera have only yet been observed in the United States 

 — Bufo and Engystoma. 



