FERTILIZATION AND EGG-SECRETIONS. 



TABLE I. 



For the agglutinins, hybridization offers a good approach. 



Just ('19) has made successful crosses between Arbacia and 

 Echinarachnius. If now the agglutinins of these forms play a 

 specific role in fertilization, one might expect that this could be 

 rendered apparent in hybridization experiments. For this reason 

 I treated the sex cells prior to insemination with species-true 

 secretion and compared the results with crosses in which this 

 treatment was not given. The experiments condensed in Table 

 II. speak for themselves. 



TABLE II. 



In these experiments I used none of the expedients so often 

 employed to break down the incompatibilities that limit success 

 in hybridization. Neither the eggs nor the spermatozoa were 

 allowed to grow stale ; no alkali was used ; there were no repeated 

 inseminations, nor were the spermatozoa added to the eggs in 

 greater quantities than usual. With the sole exception of the 

 treatment whose efficacy I wished to test, I followed strictly all 

 the procedures of ordinary species-true insemination. 



I think it must be admitted, not only that there is an effect, 

 but that this effect applies primarily to the spermatozoa. Since 



