Excerpt from Handbook of Invertebrate Zoology: For Laboratories and Seaside Work This book is a handbook, not a text-book, and the entire absence of generalizations and comparison is not due to indifference to the generalization of modern philosophical morphology, but rather to a wish to aid beginners to study them. Most lecturers upon natural science find, no doubt, that preliminary work, the presentation of the facts upon which science is based, absorbs so much time that there is no room for a philosophical discussion of the scientific aspects of the subject. I have, therefore, attempted to show the student how to acquire a knowledge of the facts for himself, in order to remove this burden from lecturers and text-books. The types selected for description are necessarily few; but I hope that a thorough study of all the forms which are here described will fit the student for more extensive research. In the treatment of each type I have not attempted to make an exhaustive monograph for the use of specialists, or to present all that is known about it; but simply to call the attention of the beginner to the structural features which he can readily observe for himself. 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.