PLATES 



I PHOTOMICROGRAPHS OF SPERMATOZOA 



between pages 1 and 1 1 

 II ELECTRON MICROGRAPH OF SPERM-TAIL 



facing page 14 



III REPRODUCTIVE TRACT OF THE BOAR 16 



IV TRACK OF THE SPERM-HEAD 42 



V PURINE AND PYRIMIDINE BASES IN SPERM DEOXYRIBO- 

 NUCLEIC ACID 102 



VI EFFECT OF CASTRATION AND TESTOSTERONE ON THE 



SEMINAL VESICLES OF BULL-CALVES 142 



VII SPERMINE PHOSPHATE 161 



XI 



