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PREFACE 



In this volume will be found descriptions of the structures and 

 life processes, together with directions for laboratory study, of a 

 number of animal types which have proved to be of outstanding 

 value for those beginning the study of animal biology. In all of 

 the descriptions a careful endeavor has been made to select the 

 relevant facts and to give a direct and uniform presentation with- 

 out unnecessary details or unimportant terms. 



The general plan of this book and much of the contents are the 

 same as in the Manual of Biology, Fourth Edition, which has been 

 so favorably received in many laboratories, but there are certain 

 important differences which should be noted. In the first place, 

 the consideration of plant types is sufficient only to give an under- 

 standing of their basic importance in animal nutrition. This 

 restriction of the plant material has permitted the inclusion of 

 several additional animal types as well as the introduction of 

 considerable new material throughout, but particularly in connec- 

 tion with vertebrate structure and function. 



Secondly, in addition to the page and figure references which 

 link it closely with the companion volume, Animal Biology, by 

 Professor L. L. Woodruff, there will be found at the end of each 

 chapter a series of page references to a number of other standard 

 textbooks in animal biology or zoology and also to a few carefully 

 chosen reference books for more detailed information ; all of which 

 it is hoped will add to the general adaptability for various types 

 of zoological courses. 



Finally, particular attention should be called to the series of 

 full-page illustrations which, with two exceptions, were drawn 

 for this Manual by Richard Edes Harrison. They are based 

 whenever possible on the study of living animals and for the most 

 part are habitat groups, definitely designed to stimulate the interest 

 of the reader in the detailed study of the various types. It is a 

 pleasure to acknowledge Mr. Harrison's ability both as a biologist 

 and as an artist, as is evidenced by these figures. Mention should 



