iv PBEFACE. 



of prepared objects for illustration. The school library of 

 reference should be supplemented by a small select museum 

 which can be formed at less expense than the library itself. 



Th'e success of class-work in Zoology depends mainly on 

 the teacher and the proper use of specimens. 



While the book begins with the simplest forms and ends 

 with the most complicated, the first lesson should be, as 

 suggested in the prefaces to the author's more advanced 

 books of this series, devoted to the examination of a fish 

 with the aid of Chapter XXI., so that the student may 

 have before him a standard by which to compare the lower 

 forms. 



Younger scholars or readers might omit the purely ana- 

 tomical descriptions, which are in small type. Indeed, 

 class-work in Zoology may be made easy or difficult, sim- 

 ply amusing and yielding useful information, or as disci- 

 plinary as the study of mathematics or the languages. To 

 become in any way disciplinary, the student should be 

 required to rigidly observe, compare, dissect, draw, and 

 write out descriptions of the specimens or dissections, thus 

 becoming an original observer and recorder. 



But the student of modern Zoology needs something 

 more than a knowledge of the structure of a few types; he 

 should watch them while alive, observe their habits, see 

 how they grow, learn how each kind of creature is adapted 

 to its peculiar life; learn, so far as is possible, how and 

 why certain groups have been successful in the struggle 

 for existence, and why others have failed. Something can 

 be done in this respect by young students. For valuable 

 hints in this direction the author acknowledges his indebt- 

 edness to Miss Buckley's interesting "Winners in Life's 

 Eace," an excellent book for collateral reading in connec- 

 tion with the class-work. 



Of the 365 wood-cuts, 111 have not appeared in the au- 

 thor's other books; of these 24 are original, having been 

 prepared expressly for this book, 16 of them (Figs. 16, 58, 

 60, 78, 80, 177-8, 195, 199, 207-11, 240-1) having been 



