G. W. HART ON OYSTERS AND OYSTER-SPAT. 239 



already penetrated a large portion of the style, fertilization is 

 much more likely to be effected by the alien pollen — that, in point 

 of fact, the second or alien pollen is pre-potent over the first. 



If the same be the case with oysters, which appears likely as 

 giving the species the best chance of surviving, it all becomes a 

 question of pre-potence. Where the oysters are scattered or soli- 

 tary, self-fertilization would have a great effect in preventing ex- 

 tinction ; whilst where they are closely packed together, the water 

 loaded with vast numbers of spermatozoads, assisted by the law of 

 pre-potence would effect cross-fertilization, the effect of which 

 would be most undoubtedly to strengthen and improve the race. 



