TO 



PROFESSOR JOSEPH LEIDY, M. D., LL. D., 



PRESIDKNT OF THE ACADEMY OF NATUEAL SCIENCES OF PHILACELPHIA, <feO., 



WHOSE PROFOUND RESEAKCHES HATE SO LARGELY TENDED TO DEVELOP 



THE SOIBNOE OF BIOLOGY, 



THIS VOLUME IS RESPECTFULLY DEDICATED. 



A. H. 



