Excerpt from Bulletin No, 6 of the Illinois State Museum of Natural History: Description of New Species of Palæozoic EchinodermataThis species is above medium size. The calyx is short, three times as wide as high, subpentagonal in outline. The vault is high and in¿ated. All the plates of the body are produced in wedge-shaped, irregular spines, part of which are broken off our specimen.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.