Excerpt from The Recent Mollusca of Augustus Addison Gould: Illustrations of the Types Described by Gould With a Bibliography and Catalog of His SpeciesIt is not to be inferred that the author regards the fixation of types as a final goal in systematics. Types are only taxonomic building blocks. We are still faced with the problem of taxonomic stability in mollusks, of making taxonomy 1864 sufficiently precise to serve the needs of taxonomy 1964 and, although the old typological concept has been replaced by the population concept, we still have to fix and clarify many of the species. In this regard, we should judge the work of older naturalists such as Gould by the best standards of their own times and not by our own.It has not been our purpose to bring up to date each of the species covered, this is a task for individual revisers. If we have helped to make this task easier and their conclusions more precise, our purpose will have been served.It gives me pleasure to thank those people whose willing cooperation has eased the task of accumulating data. Special thanks are due to Drs. Harald A. Rehder and Joseph P. E. Morrison of the United States National Museum for their ever-willing aid in searching for types, for suffering numerous interruptions in their own research, for helping with the mounting and dismounting of specimens for photography, and for performing tiresome but necessary tasks connected with the project.About the PublisherForgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.comThis book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully, any imperfections that remain are intentionally left to preserve the state of such historical works.