Excerpt from Text-Book of the Embryology of Invertebrates, Vol. 4 The Tunicates, more than any other group, seem of recent years to have occupied the attention of embryologists, and the. Large amount 'of work which has been done on this group, especially in France, with regard to both the sexual and the asexual methods of reproduction, will be gathered from the additional literature appended to Chapter xxxv., only a small proportion of which could be referred to in the footnotes. In the Mollusca also a great deal of work has been done, especially in connection with cell-lineage, and the formation of the mesoderm and of the larval kidney, in spite of which the last two points still remain obscure. Since I am more familiar with the Mollusca than with any other group of Invertebrata, I have revised the chapters dealing with this phylum some what more thoroughly than the rest of the volume; I have appended numerous notes, inserted some fresh paragraphs, and made certain alterations in the text which appeared justified. By' recent investigations. I must again express regret that so long a time has inter vened between the publication of the German edition of this. Work and the appearance of the last volume of the English translation. Volumes ii., iii. And iv. Came into the hands of the translator only in 1897, and the task of bringing them out being necessarily somewhat lengthy, it has been impossible sooner to Offer the completed work to the English-speaking student, to whom it should be of great service. 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.