vi PREFACE 



Denton, of Wellesley, Mass., Mr. L. H. Joutel, of New York City ; 

 and Mr. E. N. Fischer, of Jamaica Plain, Mass. Mr. Denton 

 made the drawings of the vertebrate dissections and the external 

 view of the lizard and Oniscus. Mr. Joutel made the drawings 

 of the insects and all the invertebrate dissections. Mr. Fischer 

 executed the drawings of all the marine invertebrates shown 

 in their natural environment, and also the ecological studies 

 of the pond-snail, the garden-slug, the garden-spider, the leech, 

 the fresh-water mussel, and the fresh-water sponge, besides 

 copying many figures from publications. Mr. Win. T. Oliver, of 

 Lynn, Mass., made the numerals and the leader-lines for all the 

 drawings. 



We desire to acknowledge the kindness of Professor H. C. 

 Bumpus, Director of the American Museum of Natural History, 

 arid of Professor H. F. Osborn, Curator of Vertebrate Paleontol- 

 ogy, American Museum, in permitting us to make selections from 

 numerous photographs. Mr. C. William Beebe, of the Xew York 

 Zoological Park, supplied us with photographs of many verte- 

 brates and some marine invertebrates. Several photographs in 

 different chapters are from, the authors' own collections. To 

 the following publishers we acknowledge the privilege of using 

 figures: American Book Company; D. Appleton & Co.; G-. W. 

 Crane & Co. ; Doubleday, Page & Co. ; Henry Holt & Co. ; McClure, 

 Phillips & Co. 



It is our hope that the quotations which introduce the chap- 

 ters will serve to suggest to the imagination of young students 

 the poetic side of animal life and of nature generally. For some 

 of the best quotations we are indebted to the search made by 

 personal friends. 



We are especially grateful to several zoologists who have read 

 various portions of the manuscript critically : Professors G. H. 

 Parker and W. E. Castle, of Harvard University ; Professor J. H. 

 Comstock, of Cornell University; Professor H. 8. Jennings, of the 

 University of Pennsylvania ; Professor M. A. Bigelow, of Teachers 

 College, Columbia University ; Dr. J. A. Allen, Mr. Frank M. 



