PREFACE. 



In the present catalogue it is proposed to present a systematic ac- 

 count of the collection of North American Serpents in the museum 

 of the Smithsonian Institution. In the Appendix will be found such 

 species not in possession of the Institution, as could be borrowed for 

 description, as well as notes on more or less authentic species of which 

 no specimens could be found. 



A complete synonomy of all the species has not been attempted, 

 as tending to swell the bulk of a catalogue too much. All those, 

 however, necessary to a proper understanding of the history or cha- 

 racter of the species, have been introduced, and all the synonyms 

 quoted have been actually verified by original reference. 



Owing to the want of osteological preparations, it has been a difii- 

 cult task to arrange the genera in a natural succession. In many 

 cases forms are now combined which will hereafter necessarily be 

 widely separated. The almost entire deficiency of modern general 

 works upon the Colubridce, has also been a serious obstacle to any 

 correct idea of a natural system. The forthcoming work of M. M. 

 Dumeril will undoubtedly clear up much of the obscurity which now 

 exists. But when systematic writers all carefully avoid the subject 

 of the Ophidians, each waiting for the others to make the first step, 

 the attempt to combine genera by well marked, though perhaps arti- 

 ficial points of relation, will it is hoped be looked upon with indul- 

 gence, even after more comprehensive and extended investigations 

 shall render it necessary to break up the combinations here adopted. 



The collections upon which the original descriptions of the present 

 catalogue have been based are as follows : — 



Spencer F. Baird. Species from Massachusetts, New York, 

 Ohio, and Pennsylvania. 



Charles Girard. Maine, Massachusetts, and South Carolina. 



Rev. Charles Fox. Species from Eastern Michigan. 



Dr. p. II. Hoy. Species from Eastern Wisconsin. 



Prof. L. Agassiz. Lake Superior, Lake Huron, and Florida. 



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