This association on a bottom so deficient in silicious sand, and the apparently decided predilection for that material found among these silicious forms, as well as their difference in shape from their calcareous congeners, leave the systematist in some sus pense as to the true relation that one set bears to the other. For the present I am inclined to consider their differences to be but of varietal importance.

About the Publisher

Forgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.com

This 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.