Excerpt from The Standard Natural History, Vol. 2 Cuvier, in his great divisions or branches of the animal kingdom, recognized a group Articulata characterized by having a bilaterally Symmetrical body, composed of a series of rings or segments serially arranged. An excellent example Of the arrange ment of these rings can be seen in the common earth or angleworm. These rings make a hardened external skeleton, which at once forms a framework for the attach ment of muscles, and also a protection for the internal organs. Typically, there is found in each segment a portion Of each Of the more important organs Of the body. Just under the dorsal surface is found an elongated dorsal vessel, which represents the heart; the intestine lies in the median line Of the body, which it usually traverses from end to end, while the nervous system, consisting of a series Of enlargements, called ganglia, connected by nervous cords, extends along the floor Of the body. This group of Articulata was still further divided into three classes: Worms, Crustacea, and Insects. 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.