128 THE SHORTER SCIENTIFIC PAPERS 



but seemingly more logical to admit that the change is a 

 secondary one and that the first maturation cells may still 

 represent the spore cells. 



In accordance with the proposition that spores unite as 

 gametes to form a single cell, evidence should either be 

 presented to show that an identical chromosome composi- 

 tion exists between the actual spores and the so-called 

 spores functioning as gametes or consideration should be 

 given to subsequent reduction division. Otherwise the 

 conclusion scarcely merits the value of an opinion. Fur- 

 thermore, the argument that the fusion of a sperm and 

 cell among the angiosperms to form a nutritive endosperm 

 justifies the conclusion that pairing and fusing do not 

 represent the essential features of sexuality, can not be 

 considered. This is only one of numerous examples where 

 changes in form or function of parts occur without hav- 

 ing any bearing on the actual origin of the part. Even in 

 this case a fusion is represented and may have a value sim- 

 ilar to that among gametes. 



It is in connection with "A Theory of Sex" that it seems 

 necessary to decidedly differ from Professor Coulter. Here 

 the two main theses are that sexuality has arisen (1) to 

 carry an organism through an unfavorable environment, 

 and (2) to make evolution more rapid by presenting a 

 greater diversity of forms. 



The first deduction is based on the proposition that 

 gametes in many plants are produced at the close of the 

 vegetative period. Such a conclusion — post hoc ergo 

 propter hoc — does not rest upon a sound basis. With the 

 fulfillment of a function having the importance of a 

 gamete production, it is quite logical that the cycle of 

 development should close, but to state that the closing of 

 the cycle has brought about the production of the gametes, 

 is quite another thing. The acceptance of this would lead 

 to the inference that gametes arose in fresh or brackish 

 water forms where pronounced seasonal changes took 

 place and not in larger bodies of water like the ocean, the 

 most probable place. 



The second deduction is a restatement of a conclusion 

 reached by Weismann {'76) to the effect that amphimixis 



