

K 



BIOLOGY 



LIBRARV 



G 



COPYRIGHT, 1903 AND 1913 

 BY THE MACMILLAN COMPANY 



Set up and electrotyped November, 1903 

 Reprinted February, 1905, August, 1907, November, 1908, 



May, 1910, June, 1911, March, 1912 



New and B^vised Edition, September, 1913 



June, 1914, February, 1916 



JKount Ipltasant Pre8 



J. Horace McFarland Company 

 Harrisburg, Pennsylvania 



