PREFACE TO THE SECOND EDITION 



The authors have corrected some errors that crept into 

 ',0Q first edition. We have added suggestions, problems, and 

 (iitestions which we hope will be of use to our fellow teachers. 

 We have diligently compared our text with the latest Ger- 

 ,.an, French, English, and American Zoologies, and we be- 

 lieve we have given the correct facts. 



The Authors. 

 September, 1917. 



iHtilo 



