xiv PREFACE. 



"The discoverers of new species have the undoubted right of imposing the 

 names, (specific,) and these ought never to be aUered. They may have a harsh 

 sound, be barbarous, or even absurd; yet all these objections are as nothing when 

 compared with the evils accompanying the multiplication of synonymes. Even 

 without any good reason many Naturahsts have presumed to change the names 

 which the discoverer of the species imposed upon them, in order to obtain what 

 appears to them uniformity of nomenclature, or rather for the purpose of 

 increasing their own importance. 



"The period is probably not very remote, when this mischievous spirit of 

 innovation shall receive an eflectual check, in consequence of credit being attached 

 only to those who develop new characters, and not to those who disturb science 

 by the fabrication of new names." 



It was my intention on beginning this work, to have included in it descriptions 

 of several new Reptiles, brought from the Oregon Territory and country south 

 of the Columbia river, by Mr. Townsend the Ornithologist, which he kindly 

 placed at my disposal; but having brought them in alcohol, their colours are so 

 much altered, that they cannot be relied upon for truth; I have, therefore, thought 

 it best to pubhsh them separately, uncoloured, in the Journal of the Academy of 

 Natural Sciences of Philadelphia. 



As it is, the work will, with a few exceptions, embrace descriptions of such 

 Reptiles only as inhabit the United States, from the Atlantic Ocean to the Rocky 

 Mountains, and from Canada to the confines of Texas. 



