PREFACE. 



IN the entire absence of any handbook of zoology 

 adapted to the grade of work in which he was engaged, 

 the author began to draw up, for use in his own classes, 

 simple guides to the study of a few common animals. 

 After repeated tests in the class-room, and under the 

 advice of a number of eminent teachers of the subject, it 

 was decided to put the work into print. 



The author takes this opportunity to thank those who 

 have so heartily aided him in this undertaking. 



Prof. Alpheus Hyatt, of the Boston Society of Natural 

 History, has generously aided in preparing the book for 

 publication. 



Pres. D. S. Jordan, of Indiana University, has read 

 most of the manuscript and proof-sheets, and has given 

 many valuable suggestions. 



Especial thanks are due also to H. Garman, Assistant- 

 Professor of Zoology, University of Illinois, for corrections 

 and suggestions on the entire manuscript and on the proofs. 



Mr. B. H. Van Vleck, Assistant, Boston Society of 

 Natural History, revised the manuscript on Echinoderms, 

 Coelenterates, and Sponges. 



As the proof-sheets appeared, from time to time, 

 they were critically read by Prof. N. S. Shaler, Harvard 



