PREFACE. 5 



originality : he only wishes to be given credit for an honest effort at 

 selecting, from the most available materials offered, that best calcu- 

 lated for introducing the beginner to the ideas and principles of 

 zoological science. lie respectfully invites the correspondence of 

 teachers who find difficulty in using the book. 



Finally, the author would gratefully acknowledge the assistance of 

 many friends and teachers and of books which were teachers. He 

 would speak of the cut on p. 212, which was kindly loaned by 

 Professor Forbes of the Illinois State Laboratory of Natural History : 

 and he would especially remember the assistance of Dr. E. A. An- 

 drews of Johns Hopkins University, who read the manuscript of the 

 text; of Professor J. H. Comstock of Cornell University, who read 

 the proof sheets of the pages relating to insects ; of Professor E. A. 

 Birge of the University of Wisconsin, who read the proof sheets of 

 the pages relating to crustaceans, mollusks, and vertebrates ; of Mr. 

 Edward Potts of Philadelphia, who read the manuscript of the pages 

 relating to the fresh- water sponge ; of his honored friend and teacher, 

 Professor Hurd of Knox College, who revised the etymological list of 

 technical terms; and, last but not least, of his wife, Anna Taylor 

 Needham, who made pen drawings for most of the illustrations. 



J. G. N. 



