IV PREFACE. 



mented by museums, monographs, and microscopes. Nat- 

 ural History has outgrown the limits of a single book. 

 Trial has proved the folly of giving the student so many 

 things to learn that he has no time to understand, and the 

 error of condemning the student to expend his strength 

 upon the details of classification, which may change in 

 the coming decade, instead of upon structure, which is 

 permanent. Of course, specialists will miss many things, 

 and find abundant room for criticism in what they regard 

 as deficiencies ; but the work should be judged by what 

 it does contain, rather than by what it does not. 



What is claimed, in the language of inventors, is the 

 selection and arrangement of essential principles and 

 typical illustrations from the standpoint of the teacher. 

 The synthetic method is employed, as being the most 

 natural: to begin with complex Man, instead of the sim- 

 plest forms, would give a false idea. Man is not a model, 

 but a monstrosity, the most modified of Vertebrates. 

 But these outlines must be filled up, on the part of the 

 teacher, by lectures, and by the exhibition of specimens ; 

 and, on the part of the student, by observation (noting, 

 above all, the characteristic habits of animals), and by per- 

 sonal work with the knife and microscope. No text-book 

 can take the place of nature, or supersede oral instruction 

 from a competent teacher. 



Suggestions and corrections from naturalists and teach- 

 ers will be thankfully received. 



In a work of this character, which is but a compound 

 of the labors of all naturalists, it would be superfluous to 

 make acknowledgments. The works referred to on page 

 397 have been specially consulted. 



