PREFACE 



there. It is of course assumed that the teacher will naturally elabo- 

 rate upon particular phases of the topics taken up in the course. The 

 anticipation of this and limitations of space have reduced the volume 

 of detailed information included. 



Many animals from west of the Mississippi River are featured in 

 this book. There has been no attempt to limit the scope of the work 

 to this region, but since many southwestern and western forms are 

 available and serve as very good illustrative material, they have been 

 utilized. It is hoped this wiU make the book more useful and mean- 

 ingful to students in these regions, as well as more teachable. 



The introduction of chapters on Animal Anomalies, Animal Re- 

 generation, Biological Effects of Radiation, Marine Zoologij, and 

 Wildlife Conservation is a slight departure from the usual textbook 

 outline, but each of these seems to the author to have enough of 

 special value and current interest to warrant presentation. The chap- 

 ters on Regulatory Glands, Animal Distribution, The Animal and Its 

 Environment, Animal Parasitism, Comparative Emhrijology, Animal 

 Behavior, and Paleontology are also presented with the feeling that 

 they are of exceptional general interest to all students, as well as 

 being thoroughly zoological. 



The arrangement of the chapters on animal groups has been some- 

 what in the order of complexity and systematic relationships. The 

 chapters are written in such a way, however, that this order may be 

 modified in any manner to suit the teacher. The chapters dealing 

 with typical Protozoa, Hydra, Planaria, Annelida, Arthropoda, and 

 Amphibia are somewhat amplified and include more detail because 

 they are so often chosen as typical groups for study. Throughout 

 the book the genus and species names have been italicized, and many 

 names of structures and functions have also been italicized the first 

 time they occur. 



The author is indebted and extremely grateful for the cooperation 

 of several teachers and specialists who have contributed manuscript 

 for chapters in their fields. For this service acknowledgment is made 

 to: J. Teague Self, University of Oklahoma, Annelida; Elmer P. 

 Cheatum, Southern Methodist University, Mollusca, and assisted with 

 Marine Zoology; Vasco M. Tanner, Brigham Young University, 

 Arthropoda; Mary Fielding, Public Schools, Waco, Texas, collabora- 

 tion on Elasmohranchii; Rose Newman, Baylor University, collabora- 

 tion on Pisces; Ottys Sanders, Southwestern Biological Supply Co., 



