PREFACE BY THE EDITOR. 
Much of the confusion which already exists in the synonomy of 
American Mollusca, has arisen from the general inaccessibility of 
the writings of Thomas Say. Scattered through numerous and 
costly works and obscure publications, they have always been ob- 
tained with difficulty, and for many years past a large portion of 
them have become absolutely unattainable. His species have been 
known to most American conchologists rather by tradition than 
from a careful study of his excellent descriptions ; a fact readily- 
accounting for the confusion which is to be found in the more 
recent American and European works. 
To remedy this evil in the department in which my personal study 
has been more particularly devoted, I collected and published, in 
1856, all Mr. Say’s descriptions of land shells. Having since then 
been requested to add the fluviatile and marine species, I have now 
undertaken to do so, hoping thereby to induce a just appreciation 
of the labors of our greatest Naturalist, as well as to increase the 
facilities of the student of American Conchology. 
This volume contains all the writings of Mr. Say on recent Oon- 
chology, excepting his “ Glossary of Conchology,” and List of 
Exotic Shells in my Cabinet.” The extracts from the numerous 
original works are given as nearly as possible in chronological order, 
the descriptions of terrestrial species being placed collectively at 
the commencement. To remedy the inconvenience of not having 
the various genera and species more nearly collated, I have added 
a complete alphabetical catalogue of all the species described in 
Mr. Say’s writings, with a reference to the date, volume, page, and 
figure of the original publication and of this reprint. To this must 
be referred all questions relating to priority of publication of any 
disputed species. 
The plates include all the figures ever published by Mr. Say, 
Plates 1 to 68, inclusive, have been printed from the original coppers 
of the “ American Conchology.” Plates 69, 70, 71, 72, are fac simi- 
les of the plates of Nicholson’s Encyclopedia. On plate 70 will 
also be found fac similes of the figures of Modiola opifex, from the 
Journal of the Academy, Plates 73 and 74 are printed from the 
