450 THE FERTILIZATION AND DEVELOPMENT OF FLORIDE^. 



sporogenous-filament came into contact with the auxiliary-cell, and 

 Prof. Oltmanns draws a comparison between this and the forced 

 growth of cells resulting from the invasion of a fungal energid. He 

 recommends further investigation of this point. 



Callithamnion conjmbosum and Dasya elegans are then described 

 as regards the development of their fruit. The auxiliary-cell nucleus 

 of D. elegans shows no such desire to flee from the sporogenous 

 nucleus as in the case of Biulresnaya ; the two nuclei remaining 

 contentedly near each other as in Glceosiphonia. 



It is pointed out that there is a striking resemblance between the 

 fusion of the sporogenous-filameuts and the auxiliary-cell on the 

 one hand, and the behaviour of the pericentral cells of Poli/sipho7iia, 

 described by Prof. Rosenvinge, on the other (Bot. Tidsskrift, xiv. 11 

 (^1884) ; xvii, 10 (1888) ). The nuclei of the pericentral cells, situated 

 at some distance from the apex, divide, and a small cell is cut off at 

 the outer corner. This small cell then fuses with the pericentral 

 cell immediately below it, and the nucleus of the small cell passes 

 over into the pericentral cell. 



After describing the five different types mentioned above and 

 the behaviour of the nuclei in the formation of their fruit, Prof. 

 Oltmanns proceeds to draw up a table showing the order of classi- 

 fication of the FloridecB. As he says himself, this does not differ 

 materially from that of Prof. Schmitz. His points of difference 

 with that author, as well as with Prof. Hauptfleisch and Prof. 

 Bradley Davis, are dealt with, and a fall explanation is given of his 

 systematic table. This table only takes into consideration the 

 sporogenous-filaments, cells and nuclei, without equal regard to the 

 manifold varieties in origin and position of the auxiliary-cells. If 

 this side of the question were taken into account, a new system of 

 classification would be rendered necessary. The present system is 

 therefore one-sided. Prof. Oltmanns' own feeling about the matter 

 is, that the position and development of the auxiliary-cells differ 

 according to the needs and peculiarities of various species ; and this 

 view seems to him to be all the more likely considering the tendency 

 to fusion throughout all the Florideae. This tendency arises possibly 

 from the necessity of facilitating transmission of food-material 

 more thoroughly than could take place through the cell-membrane; 

 though the fusion may also act in some cases as a convenient form 

 of anchorage. 



The systematic classification of Prof. Oltmanns is founded, as 

 said above, on the sporogenous threads and their development, if 

 one may use the term development for a growth which works back- 

 ward. At the bottom of the system the sporogenous-filaments are 

 longer and wander farther than in the more highly developed groups 

 such as PihodomelecB, where the auxiliary- cells are so closely connected 

 with the carpogonial branch as to be only separated from it after 

 fertilization has taken place. Thus the sporogenous-filament is so 

 shortened that it is hardly possible to apply the term to the short 

 outgrowth which fuses with the auxiliary-cell. 



Prof. Oltmanns likens the fusion of sporogenous-filament and 

 auxiliary-cell to the parasitism of many fungi. The sporogenous 



