Main Lib. 

 Agric, Dept. 



LIBRARY Of CONGRESS 

 Two Copies Received 



OCT 23 1908 



Copyright Entry 



BIOLOGY 



LIBRARY 



G 



Set up, electrotyped, printed, and copyrighted October, 1891. Reprinted October, 

 1892. Revised, reprinted, and recopyrighted May, 1893. Reprinted June, 1894. 

 Revised, reprinted, and recopyrighted November, 1896. Reprinted Octo- 

 ber, 1898. Revised, reprinted, and recopyrighted March, 1900. Re- 

 printed May, 1903. Revised, reprinted, and recopyrighted 

 August, 1904. Reprinted October, 1905, and August, 

 1907. Revised, entirely reset, reprinted, and 

 recopyrighted September, 1908. 



Copyright, 1908, by W. B. Saunders Company. 



OUPUC.s r E 



\^ f.yci!r 



PRINTED IN AMERICA 



PRESS OF 



W. B. SAUNDERS COMPANY 

 PHILADELPHIA 



