Excerpt from A Monograph on the British Fossil Echinodermata From the Oolitic Formations, Vol. 4: Containing, the Echinolampidae, the Stratigraphical Distribution of the Oolitic Species, the Bibliography of the Echinodermata, and Additional Notes on the Echinoidea IN the Appendix to the Crag Mollusca, ' p. 323, is the notice of a fossil which I have there assigned, with doubt, to the Genus Aplysia, conceiving it to have been the calcareous portion of an internal shell and as it is important that errors of this kind should not remain uncorrected, I take the earliest opportunity of making the corree tion. In the living Aplysia there is a shell or shield situated on the back of the animal, encysted in the mantle, covering the branchial region; and although this internal shell in the recent state is thin and coriaceous, I thought it possible there might be sufficient calcareous matter in the shell of some species of that genus to permit its being preserved in a fossil state. In this I have been mistaken. Considerable doubt was entertained by me at the time of publication, but it was my desire to have everything figured that appeared to be in any way connected with the Mollusca of the Crag. 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.