PREFACE 



might be required to master only generalizations, 

 while advanced students might be held responsible 

 for details and outside readings. With these al- 

 ternatives in mind, each chapter was conceived as a 

 self-contained, yet related unit, thus requiring some 

 repetition of material. Should it prove necessary, 

 an instructor can change the order of chapters or 

 omit entire chapters. 



Selected readings are provided with each chapter. 

 These references are books or review articles that 

 are considered primary sources of additional informa- 

 tion. They range from popular to technical, and 

 many of them contain excellent bibliographies. 



Terms are placed in italic type and defined in con- 

 text where first used in a chapter and a glossary 

 provides their precise definition. In general, only 

 terms commonly used by laymen were omitted from 

 the glossary. 



Most illustrations are original or redrawn and 

 modified from existing figures. Some illustrations 

 were supplied through the courtesy of other authors, 

 and publishers and sources are credited in the figure 

 captions. Dr. Malcolm Jollie was especially helpful 

 in allowing the use of many excellent illustrations 

 from his book Chordate Morphology. 



Many individuals contributed to the preparation of 

 this book. To Dr. Mathew F. Vessel, San Jose State 

 College, who read the entire manuscript, I am in- 

 debted for especially detailed criticisms and sug- 

 gestions, particularly for a reduction in terminology 

 and details. Dr. Robert G. Colodny, University of 

 Pittsburgh, provided a great deal of special informa- 



tion, criticisms, and suggestions for the first five 

 chapters. Drs. Jay Savage, University of Southern 

 California, and Richard A. Boolootian, University of 

 California at Los Angeles, reviewed the entire manu- 

 script and provided suggestions, criticisms, and en- 

 couragement. Dr. S. Conrade Head, University of the 

 Pacific, submitted periodic detailed criticisms and 

 suggestions, especially on the ecology chapters, while 

 using a mimeographed edition of this book in his 

 course. Dr. Kenneth L. Gordon, Oregon State Uni- 

 versity, through his course. Natural History of 

 Oregon, was the source of many ideas, including 

 some relating to the scope of the book. 



Special thanks are accorded the many teachers, 

 nature councilors, naturalists, and students for help 

 in all aspects of the book. 



Dr. Peter Gray, University of Pittsburgh, Consult- 

 ing Editor to the Publisher, reviewed the original 

 manuscript and was most helpful and encouraging in 

 various aspects of final manuscript preparation. Mr. 

 James B. Ross, Mr. R. Murray Chastain, and Mrs. 

 Elisabeth H. Belfer, all of Reinhold Publishing 

 Corporation, went well beyond their duties in fa- 

 cilitating publication. 



To these individuals I extend my appreciation and 

 thanks. Their criticisms and suggestions were most 

 helpful in the preparation of the final material for my 

 text. However, the final content of the book is the 

 sole responsibility of the author. 



San Luis Obispo, (.'alifomia 

 Angus I, 1963 



RiCII.ARD A. PiMENTEL 



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