Excerpt from Monograph of the Land and Freshwater Mollusca of the British Isles: Zonitidae, Endodontidae, Helicidae It is further very gratifying to find that the truth of the principles governing the Distribution of Life propounded in the present work, and firmly based on organic structure, continues to be increasingly supported by the additional knowledge acquired; while the especial suitability of the land mollusca for revealing the routes of dispersal from the primary evolutionary area was emphatically proclaimed by the late Karl Semper, who after many years' examination and study of many hundreds of species was led more and more strongly to the conviction that a knowledge of the affinities of the land mollusca would probably enable the paths of their dispersion to be determined. The co-operation and help which I have received in the past from so many well-wishers has been continued during the preparation of the present volume, and I again recall with grateful appreciation the immense help I still continue to derive from the results of the unwearied and nu selfish labours of the late Mr. Charles ashford, who for so long a period devoted himself to a study of the anatomy of our British mollusks for the benefit of the present work. 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.