36 



ILLINOIS ACADEMY OF SCIENCE 



Symbols 







sperm 

 receptor 



foreign 

 sperm 



combining 

 group 



_spermophile 

 group 



fertihzin 



_ovophile 

 group 



£ anti-fertiiiz 1 



egg 

 receptor 



blood 

 inhibitor 



Figure I 



DESCRIPTION OF FIGURE 



Fig. 1. In successive sectors of the egg there are represented the 

 mechanism of fertilization and the blocks to the mechanism, as fol- 

 lows: 



Sector 1. The arrangement of substances in the unfertilized 

 egg and in the spermatozoon that are active in fertilization. See ex- 

 planation of symbols. 



Sector 2. The mechanism of normal fertilization. The sperm re- 

 ceptor unites with the spermophile group of the fertilizin and the 

 egg-receptors with the ovophile group of the fertilizin owing to 

 activation of the latter by the sperm (a). Molecules of the anti- 



