There are few departments of natural science which, to American naturalists, have given rise to more investigation than the history of the reptiles of our widely-extended country. Within a very few years, most important facts have been elicited, and many new and interesting species have been added to a list, formerly extensive. The great obscurity and confusion peculiarly prevalent in the descriptions of Authors who have written on this subject, though gradually dissipating, are by no means sufficiently cleared. To the student of Herpetology, whether general or local, a systematic arrangement of all the N. A. Genera, with scientific descriptions of their species, cannot but be a desirable object.