Excerpt from Bulletin No; 1 of the Illinois State Museum of Natural History: Springfield, Illinois, February, 1882 Body above the medium size, obconic, gradually swelling from a truncated base to the summit of the radial plates, where it is about one-fourth wider than high. Basal plates as wide, or a little wider, than high, forming by themselves a low pentagonal cup, about twice as wide as high. One subradial on the anterior side IS longer than wide, the others about as wide as long, all pentagonal, there being but two distinct angles on their lower margins. Radials nearly once and a half as wide as high on the anterior rays, curving in on their lateral borders so as to give a pentalobate character to the upper part of the body. 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.