A text-book in general zoölogy

Introduction

The arrangement, presentation, and selection of the subject-matter in the present text-book have been determined by the experience gained from the labors of ten years in the class room with the grade of students for whom this work is intended. In fact, the text is simply a more orderly discussion of the same subjects in the same sequence that have been presented for ten years to successive classes in elementary zoology. The author, in his work with these students, has attempted to interpret, with much thought and care, the zoological demands of such students according to their average receptivities and practical needs rather than by any preconceived ideas of what constitutes a knowledge of zoology. The aim has been to create an interest in nature, beget an acquaintance with the lives, habits, and activities of animals, train the powers of observation, quicken the judgment, widen the horizon of environment, augment the capabilities for independent thinking, and inculcate an unswerving regard for the truth.

The instruction that a potential citizen receives in zoology must give more than a mere acquaintance with animals. If the study of this science does not accomplish the objects enumerated in the foregoing paragraph, it loses its highest value as an educational subject in the curricula of the common schools. That the study of zoology may fulfill its function as a subject of mental discipline and, at the same time, give to that large majority of pupils who become "ordinary citizens " an acquaintance with animals, the author has been led, from his experience in teaching, to include in a zoological course a goodly amount of natural history and comparative anatomy, a large share of animal ecology, economic zoology and physiology, a moderate amount of classification, embryology, and paleontology, something of the history of zoology, and, through all, a persistent presentation of the relationships of animals and of the manner in which they have been evolved. To present the foregoing divisions of the subject-matter of zoology in their proper relations and proportions is indeed a difficult task, and one which, at best, is open to criticism ; but it is hoped that the pupils who follow the course here laid down will gain an acquaintance with animals and acquire an interest in them, and, at the same time, receive that mental discipline which they would derive from the pursuit of other studies.

4 INTRODUCTION

Each branch of animals has been introduced by a familiar and accessible type. The discussion of the type is intended (1) to express, in an organized form, the details of the work already supposed to have been done in the laboratory and field, and (2) to bring out the characteristics of the branch of which the type is an example. After the different forms of the branch have been studied, their characteristics are summed up, their adaptations to environment and their economic significance are discussed, and, lastly, a clear, concise classification of the group is given. In the main, the classification accords with that given by Parker and Haswell.

The author is greatly indebted to the following men who have read and criticised parts of the manuscript, covering, in most cases, their own special fields : Dr. Gary jST. Calkins and Dr. Henry F. Osborn of the American Museum of Natural History; Professors John Henry Comstock and G. D. Harris of Cornell University ; Dr. T. B. Palmer, Dr. H. F. Merriam, Dr. Leonard Stejneger, Dr. Ch. Wardell Stiles, and Dr. B. W. Evermann of Washington, D.C. ; Dr. J. G. Needham of Lake Forest University; Dr. C. Co Nutting of Iowa University; Professor J. S. Kingsley of Tufts College; and Mr. Edward Potts of Philadelphia. It is to be distinctly understood, however, that these men are in no way responsible for any part of the work.

Most of the drawings were made by Miss Minnie Walker. Much is due to her untiring enthusiasm and devotion for the completion of the work. Several figures were redrawn from the " Standard Natural History," a few from Packard's " Zoology," with the author's permission, several from the publications of the United States Geological Survey, and Figs. 143 and 235 from Jordan and Kellogg's " Animal Life." Figure 93 was kindly loaned by the Minnesota State Experiment Station; Fig. 201 is from a photograph by Professor H. Garman ; Figs. 110, 138, and 199 were loaned by the Cornell Nature Study Bureau; Figs. 99, 100, and 101 are after Snodgras ; Figs. 95, 96, 97, and 98 were drawn by Miss Clara S. Ludlow, while a graduate student in biology. Figure 88 is from a photograph by Professor J. H. Comstock; Figs. 191 and 193 are from photographs by Dr. C. M. Weed; Figs. 179 and 197 are from photographs by Dr. R. W. Shufeldt, while Fig. 118 is from a photograph by Mr. Victor Lowe, Geneva, New York. Figure 4 was drawn from nature by my wife, to whom acknowledgment is also due for information regarding the etymology of many words, careful criticism of the manuscript, and helpful suggestions concerning the subject-matter. The remainder of the photographs, drawings, and diagrams are by the author.

GLENN W. HERRICK.