Names of classes, orders and other large taxonomic groups have not 

 been used in most cases in the keys, where animals are keyed to genus and 

 species. Zoologists are not in perfect agreement as to the application of these 

 terms, since the rules of the International Committee on Zoological Nomen' 

 clature cover only family, genus and species. Also we feel that the main 

 outlines of taxonomy and the complicated foundations of anatomy and physi' 

 ology upon which they rest can best be learned from standard zoological 

 textbooks and are likely to be confusing if inserted in the keys, especially since 

 a number of the animals included do not possess all the characters regarded 

 as typical for the groups in which they are placed. To acquaint the student 

 with the general form of such grouping, to make the reference books more 

 easily consulted, and to give him some preliminary benefits of the use of the 

 larger groups in grasping the idea of relationships, we have given, at the end 

 of the discussion in each chapter, an annotated outline of the general scheme 

 of classification of the group. The more readily observed characters which, 

 taken in combination, distinguish the native forms in these large groups, have 

 been listed. Wherever feasible, family names have been included in the keys. 



Many scientific names have been changed within the last quarter century, 

 due in part to our better knowledge of animal relationships and in part to 

 the researches among the long ignored or overlooked writings of early American 

 naturalists, who now receive long delayed credit for the application of many 

 scientific names. We have endeavored, in most cases, to use as first choice the 

 scientific names given in a recent check list for each group. In cases where 

 another name is still in general use it is given as second choice, except where 

 otherwise noted, and also the synonym or synonyms are given that are most 

 likely to have been used as the scientific name or names in the available 

 literature. 



A complete list of the publications consulted in compiling these keys 

 would double the size of the book, so we must limit ourselves to a general 

 grateful acknowledgement to all who have worked on the classification of 

 American animals, with a special vote of thanks to those whose careful and 

 critical studies in the compilation of check lists award credit where it is due 

 and help to stabilize the use of scientific names. We are also greatly indebted 

 to museums, friends and collectors who have made it possible for us in a great 

 many cases to check the keys with actual specimens, either living or preserved. 



We fully realize that some errors may have crept into this book, but we 

 trust that the good outweighs the bad and that our efforts may be of some 

 aid in bringing about a greater knowledge, and consequently a greater ap- 

 preciation, of our wild animal life. 



