PR E FA CE. 



In presenting this thesis the writer would state that it 

 has been his aim to prepare a work which would facili- 

 tate the study of these animals. In the effort to accom- 

 plish this, he has not hesitated to use the works of pre- 

 vious authors, and as some may wish to know how 

 much has been taken from his predecessors, and others 

 desire the means of fuller investigation, he has appended 

 at the end a list of the works from which he has drawn 

 material. While under more or less obligation to all 

 these authorities, he feels that an especial mention is due 

 to the Erpetologie generale, by Dumeril and Bibron; 

 the article Amphibia in the Encyclopaedia Brittanica, by 

 Prof. Huxley, and the papers of Prof. Cope. 



In addition to the authors cited, he has availed himself 

 of the specimens in the University collection, and so far 

 as possible relied upon these rather than the writings of 

 his predecessors, fully believing that book knowledge, 

 however good, when compared to an examination of 

 the object, is like the dry bones in the prophet's vision. 

 So far as facilities were at hand, the descriptions and 

 characters have been drawn from the object. Where 



