PREFACE. 



THIS book is a companion to a course of Systematic Zoology. The need of such 

 a book lias become obvious to us from some years of teaching. The study of 

 Class-Types, now a part of every systematic course, is already well provided for 

 by Professor EOLLESTON'S " Forms of Animal Life," and the many books that 

 have modelled themselves upon it. The Zoological Laboratory, too, is not 

 without its many and admirable Text-Books. There is room, however, and 

 need for a form of book such as we offer to the public in these Illustrations of 

 Zoology. In it the student will find illustrated, by Diagram or Drawing, the 

 structure of forms selected from all the great Classes of Vertebrates and 

 Invertebrates, and the illustrations arranged in systematic order. Our design is 

 to help the student of Comparative Anatomy in the most important and the 

 most difficult part of a systematic Course of Lectures. 



In dealing with the Vertebrates, we could have wished to illustrate types of 

 all the Orders as well as of the Classes, but to have done this would have made 

 the book larger and more expensive without making it proportionally more 

 useful. Besides, the general text-books, as a rule, give with a fair degree of 

 fulness the chief features of the Vertebrate Orders. 



The system of class-naming that we have followed is the system used by 

 the late Professor F. M. BALFOUR in his Classification. We give in an Appendix 

 a Classified Index, showing the forms illustrated according to the system of 

 classification used by GLAUS. 



The Drawing in Plate 46, Fig. 4, is taken, with Messrs. MACMILLAN & Co.'s 

 kind permission, from Professor HOWES'S " Elementary Atlas of Biology." The 

 Diagram in Plate 15, Fig. 5, is one of VON GRAFF'S, modified by JOHN BLAND 



