PREFACE Vll 



we are indebted to Messrs. Ileniy Holt & Go. For Figure 415 

 we have to tliank tlie Cambridge University Press, and for 

 Figure 416 tlie Eay Society. For Figures 317, 318, 319, and 

 34<S we are indebted to tlie New York Zoological Society 

 through its Director, iJr. W. T. Hornaday. 



During the jiast ten years, we have received numerous photo- 

 graphs of animals and habitats. Some of these have l)een 

 reproduced for the most part without naming the donors, but 

 none the less with high appreciation of the gifts. 



Finally, we have to thank those teachers who have made 

 nsefrd suggestions as to how the book could be improved. 

 We have had helpful criticisms from j\[r. J. H. Emerton on 

 the Spider Chapter, and Mr. W. L. W. Field of the Milton 

 (Mass.) Academy has read the entire manuscript carefullj^ 

 and made many suggestions that we have carried out. 



It seems improbable that with our increasing submersion 

 in scientific investigation we shall ever be al)le to offer another 

 revision of this book ; nevertheless, we shall prize a continua- 

 tion of that criticism and suggestion from teachers who use 

 the book which in the past has brought us many friends. 



CHAIILES B. DAVENPORT. 

 GERTRUDE C. DAVENPORT, 



Cold Spring Harbor, Lo.vg Island, N.Y., 

 November 28, UllO. 



