Fertilisation in Cryptogams 175 



tion of these two parts we owe chiefly to Zacharias, who 

 thoroughly investigated the micro-chemical reactions of 

 the male reproductive cells, and pointed out repeatedly 

 the different behavior of their external and internal 

 parts. 13 The nuclein especially forms the chemical char- 

 acteristic for the substance of the nuclei. Fluids which 

 easily dissolve and extract this substance remove only the 

 inner part of the spermatozoids and leave the outer layer 

 and the cilia in general undissolved. In return the cilia 

 dissolve in pepsin, and do not, therefore, consist of nu- 

 clein. 1 * According to Campbell, also, the cilia of the sper- 

 matozoids are not developed from the nucleus, but from 

 the cytoplasm of the mother-cell. 15 



But, during fertilization evidently the nucleus alone 

 plays a part. The deep penetration of the entire sper- 

 matozoid into the egg-cells teaches that there is no prob- 

 ability of a conjugation of its outer layer with that of the 

 egg-cell. More likely do this organ and the cilia dis- 

 appear within the egg-cell, without playing any note- 

 worthy role therein. 



Exceptionally the spermatozoids possess small chromat- 

 ophores which, perhaps, they may need on the way to the 

 egg-cell, either for taking the right direction, or for other 

 purposes. An example is found in Fucus, where Schmitz 

 proved that they arise by division from the chromato- 

 phores of the mother-cell. 16 But no observation teaches 

 that they play any role in fertilization. 



Phylogenetically, the spermatozoids of the algae have 



isZacharias. Bot. Zeit. 1881-1888. 



14 Zacharias, E. Ueber die Spermatozoiden. Bot. Zeit. 39: 828, 

 836, 850. 1881. 



15 Campbell, D. H. Zur Entwickelungsgeschichte der Spermato- 

 zoiden. Ber. Deut. Bot. Ges. 5: 120. 1887. 



16 Schmitz, loc. cit. p. 122. 



