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BIOLOGY 

 UBBARY 







RICHARD CLAY AND SONS, LIMITED 



BREAD STREET HILL, E.C., AND 



BUNGAY, SUFFOLK. 



First Edition, printed 1875. 

 Reprinted 1875, 1882, unth slight corrections 1885, 1890, 1893 1897) 1903, 1909. 



