PREFACE TO THE FIRST EDITION. 



THE present volume is intended as an introduction to 

 the serious study of zoology. It embraces directions for 

 laboratory work upon a selected series of animal types and 

 a general account of related forms. Laboratory guides 

 are somewhat numerous, but general outlines of zoology 

 adapted to beg'nners are few. By combining the two, 

 it has been possible to emphasize the comparative side of 

 the subject. A knowledge of isolated facts, no matter 

 how extensive, is of little value in education, excepting 

 as the powers of observation are trained in ascertaining 

 those facts. Nature studies are truly educational only 

 when the student is trained to correlate and classify facts. 

 A considerable experience with students of different ages 

 has resulted in the conviction that it is not sufficient to 

 ask one to compare a grasshopper and a beetle, pointing 

 out their resemb.ances and points of difference; leading 

 questions must be asked. When the student has answered 

 the questions under the headings " Comparisons ' in the 

 following pages, he has a tolerably complete statement of 

 the principal characters of the larger groups of the animal 

 kingdom. 



Several considerations have had weight in the selection 

 of types to be studied in detail. In the first place, so far 

 as possible, these should be such as are readily obtainable 

 in any locality. But there are certain important groups, 

 all the members of which are marine. The forms of these 



