614 LECTURE XXII. 



already described in that they are not naked motile masses of 

 protoplasm like these, but are enclosed in a cell-wall, and are 

 not motile : they are sometimes spoken of as antherozoids, 

 but it is convenient to distinguish them as spermatia. The 

 female organ also is peculiar. It may consist of one or of 

 many cells ; but whatever its structure it always presents the 

 following characteristic features : it is permanently closed : it 

 exhibits a distinction into two parts, the one a filamentous 

 receptive part, termed the trichogyne, and a more or less 

 dilated portion, the carpogonium, the whole organ being termed 

 &procarpium; and finally no female reproductive cell of the 

 nature of an oosphere can be detected within it. The sexual 

 process takes place in this manner. The spermatium (anthero- 

 zoid) is brought passively into contact with the trichogyne; 

 complete fusion takes place so that the contents of the sperma- 

 tium pass into the trichogyne. When this has occurred the 

 trichogyne withers and changes become apparent in the basal 

 carpogonial portion of the procarpium. If it is unicellular it 

 divides, and if multicellular one or more of its cells (carpogenous 

 cells] divide, and by a process of budding a cluster of cells is 

 produced, which frequently becomes invested by an upgrowth 

 of tissue from the neighbouring vegetative cells of the plant. 

 This fructification is termed a cystocarp. The cells thus pro- 

 duced are spores, that is to say, they are capable each by itself 

 of giving rise to a new plant, and they are distinguished as 

 carpospores to indicate the peculiarities connected with their 

 production. 



The sexual production of spores in the Florideae is of 

 special interest in that it affords us an example of a sexual 

 process taking place, not as in the cases already considered 

 between two sexual reproductive cells, but between a repro- 

 ductive cell, the spermatium, on the one side and the undif- 

 ferentiated protoplasm of a female organ on the other. It is, 

 as we have seen, only as a consequence of fertilisation by the 

 spermatium that a formation of reproductive cells takes place 

 in the carpogonium ; and the cells then formed are not female 

 reproductive cells, but are spores. The significance of the 

 facts is this, that in consequence of the fusion of the sperma- 



