IV INTRODUCTION. 



adds anything of moment to their history, they are noted as 

 being from such or such a collection. 



In the adoption of generic and specific names, it has been 

 thought right to use, whenever it was possible, that which was 

 first appUed to the species. As far as regards the specific 

 names, there is comparatively little difficulty in the applica- 

 tion of this simple rule ; but generic names have been used 

 by different authors in senses so widely different, and the 

 groups which they were meant to designate have been so va- 

 riously extended or restricted, that it is no easy matter to de- 

 termine, where several names have been used, which of them 

 ought to be preferred. And as every original observer will 

 constantly make use of characters which others may have over- 

 looked, or not thought of so much importance as he may be 

 inclined to attach to them, even when a generic name is used, 

 it will of necessity be often employed in a different sense, or 

 with a more restricted or extended meaning than its original 

 2)roposer applied to it. 



It is needless, however, to enter into the details of nomen- 

 clature, further than to observe that to the name adopted for 

 the genus, is appended the specific name under which the ani- 

 mal is believed to have been first described. If the generic 

 name adopted be different from that employed by the esta- 

 blisher of the species, his name immediately follows it as a 

 synonyme ; and where the animal has received mo)*e than one 

 specific name, these names are also given. But it has been 

 thought unnecessary to load the Catalogue with any other ge- 

 neric names, where no change has been made in the specific, 

 as it has been considered that these names will be sufficient 

 for all the purposes of identification. 



In those cases where the two sexes of the same species, or 

 any particular individual state or variety belonging to it, has 

 been differently named, such names (belonging exclusively to 

 the state or individual so described) are placed after the refe- 

 rence to the specimen to which they generally apply. 



To detennine with accuracy the names and synonymes ( ' 

 the species, the Museums of Paris, Leyden, Vienna, Berlii 

 Francfort, &c., have been personally examined. Many of tt 

 specimens in the Museum collection have been received froi 

 the original describers, and most of them have been examine' 

 by M. G. Bibron, one of the autliors of the Erpetologi 



