606 THE AMEBIC AN NATURALIST [Vol. XLIV 



some or set of chromosomes — are features which can not 

 find consideration within the limits of this paper. I 

 wish to state also that in the use of the expression, 

 sexual reproduction, I shall keep in mind primarily, and 

 for the sake of clearness, what will be called a complete 

 sexual angiosperm, hereditarily speaking, that is, one 

 with a complete life-cycle, embracing both sporophyte 

 and gametophyte. Such an individual arises from the 

 fusion of egg and sperm, each with the haploid number 

 of chromosomes. The product of this fusion must de- 

 velop into an adult sporophyte, capable of producing 

 functional micro- and mega-spores, each with the haploid 

 number of chromosomes. From this it will be seen that 

 the mere fusion of gametophytic cells or nuclei is not 

 necessarily regarded as a sexual process. It is to be 

 understood also that the writer does not consider it 

 imperative to stay within the confines of the foregoing 

 definition, for like nearly all general definitions, this is 

 made for convenience and for greater clearness in the 

 general presentation. 



No profounder statement lias been made within the 

 past half century than when it was said that the union 

 of two sexual cells created a new individual — the indi- 

 vidual with just twice the number of chromosomes as 

 that possessed by either parent cell, namely, a sporo- 

 phyte; for is it not the sexual process that makes pos- 

 sible all those phenomena understood by the expression, 

 transmission of parental characters to offspring? And 

 I mean especially the transmi>Mon of characters of two 

 direct parents to each new generation. In this connec- 

 tion may we not ask also whether hereditary phenomena, 

 such as engage the attention of biologists at the present 

 day, exist among those simple plants in which sexual 

 reproduction does not occur? Is there such a thing as 



this paper prohibit an attempt at an answer to the last 

 two questions at this time. We shall have in mind then 

 those characteristics which are handed down from par- 

 ents to offspring. Some of these characters may mani- 



