THE AMERICAN 



MONTHLY 



Microscopical Journal 



CONTAINING 



CONTRIBUTIONS TO BIOLOGY. 



Volume XTII. 



FOR 



1893 



FOUNDED IN 1880, BY ROMYN HITCHCOCK, F. R. M. S. 



PUBLISHED. SINCE 1887, BY CHAS. W. SMILEY, 



WASHINGTON, D. C. 



