GAMOGENESIS. 33 



the influence of the male, is that which undergoes division 

 and eventual development into independent germs ; but there 

 are some plants, such as the Flor ideas, in which this is not 

 the case. In these, the protoplasmic body of the trichogyne, 

 which unites with the spermatozooids, does not undergo 

 division itself, but transmits some influence to adjacent cells, 

 in virtue of which they become subdivided into independent 

 germs or spores. 



There is still much obscurity respecting the reproductive 

 processes of the Infusoria ; but, in the Vorticellidas, it would 

 appear that conjugation merely determines a condition of the 

 whole organism, which gives rise to the division of the endo- 

 plast or so-called nucleus, by which germs are thrown off; 

 and, if this be the case, the process would have some analogy 

 to what takes place in the Florideas. 



On the other hand, the process of conjugation by which 

 two distinct Diporpce combine into that extraordinary double 

 organism, the Diplozoon paradoxum, does not directly give 

 rise to germs, but determines the development of the sexual 

 organs in each of the conjugated individuals ; and the same 

 process takes place in a large number of the Infusoria, if 

 what are supposed to be male sexual elements in them are 

 really such. 



The process of impregnation in the Floridece is remark- 

 ably interesting, from its bearing upon the changes which 

 fecundation is known to produce upon parts of the parental 

 organism other than the ovum, even in the highest animals 

 and plants. 



The nature of the influence exerted by the male element 

 upon the female is wholly unknown. No morphological dis- 

 tinction can be drawn between those cells which are capable 

 of reproducing the whole organism without impregnation 

 and those which need it, as is obvious from what happens in 

 insects, where eggs which ordinarily require impregnation, 

 exceptionally, as in many moths, or regularly, as in the case 

 of the drones among bees, develop without impregnation. 

 Even in the higher animals, such as the fowl, the earlier 

 stages of division of the germ may take place without im- 

 pregnation. 



In fact, generation may be regarded as a particular case 

 of cell-multiplication, and impregnation simply as one of the 

 many conditions which may determine or affect that process. 

 In the lowest organisms the simple protoplasmic mass divides, 

 and each part retains all the physiological properties of the 



