BIOLOGY 

 LIBRARY 



G 









Copyright, 1910, by W. B. Saunders Company. Reprinted July, 1911. 

 Revised, reprinted, and recopyrighted November, 1913 



Copyright, 1913, by W. B. Saunders Company 



PRINTED IN AMERICA 



PRESS OF 



W. B. SAUNDERS COMPANY 

 PHILADELPHIA 



