THE CROTALIDyE. 383 



their form, a fourth their teeth, a fifth their habits, and 

 so on, and that even at the present day the classification 

 of them is far from complete, the present writer will be 

 absolved from attempting anything beyond generalization. 



Studying snakes towards the end of the last century, 

 were Laurenti, Buffon, Bonnat, Lacepede, Klein, Seba, etc. 



In the early part of the present century were Latreille, 

 Shaw, Daudin, Oppel, Merrem, Wagler, Neuwied, Cuvier, 

 and many others till we come to Gray, Fitzinger, and 

 Dumeril, 1844. This last author, in his introduction to 

 Les serpents solenoglyphes, dit ThanatopJiidcs, includino- the 

 most deadly snakes, devotes several pages to the subject of 

 the 'pit,' and why it had especially occupied the attention of 

 those herpetologists who were endeavouring to improve the 

 previously imperfect systems. Wagler in 1824 assigned the 

 name Bothrops (from /SotJ^oc, any hole, or pit, or hollow duo-) 

 to vipers with the pit that had only scales and no plates or 

 shields on their head, separating these from the rattlesnakes 

 and from those that have shields (see illus. p. 318). This 

 nomenclature of Wagler's did not commend itself to other 

 herpetologists, and Fitzinger, in his Sy sterna Reptiliiim, 1843, 

 extending the group, retained the name for one of the five 

 families into which he divided all the venomous snakes. 

 Fitzinger's fifth family, the Botlirophides, included some of the 

 Indian pit vipers ; but as some of these latter have shields 

 on their head, they could not be admitted into Wagler's 

 group with scales only. As the present object is to demon- 

 strate some of the perplexities of naturalists, and to arrive at 

 the reason why so many snakes without the crotalon are 

 called Crotalidce, we will quote Dumeril's reasons, invitino- 



