164 THE EVOLUTION OF LIVING BEINGS. 



can therefore say that, if it could be proved that a moss 

 plant were able to produce more than one kind of ga- 

 metes, mutation would have been proved in so far at 

 least, as we would be justified to conclude, from such a 

 result, that a monogametic organism can become poly- 

 gametic without the direct interference of a cross. 

 Experiments with mosses, from which of course 

 hybrid diploid generations can be obtained, viz hybrid 

 capsules, are therefore highly advisable, also because 

 they can throw light on the question of gametic purity, 

 the nature of every separate gamete here becoming vi- 

 sible in the mossplant, which arises from it, while hi 

 diploid organisms we can see but the effect of the in- 

 teraction of two gametes. 



