ARCHER ON " PALMOGLffiAN" ALGJE. 2f>7 



cancy or import of that act. Prom his saying that is " merely an act of 

 fusion, not of impregnation,"* I infer that he conceives that it has no 

 special significancy. But can a phenomenon which has heen going on 

 for years and years uncountable, since Conjugatae were — restricted, 

 with a few exceptions, as it is, to the group so denominated, and the 

 Diatomaceae — be simply accidental, and quite devoid of all significancy ? 

 I cannot believe it reasonable to suppose that it should be so. 



I believe that the phenomenon of conjugation can be regarded as no- 

 thing less than an indication of a distinction between germ-cell and 

 sperm-cell, the humblest manifestation (it may be) of a difference of sex, 

 which becomes by degrees more and more forcibly pronounced in the 

 higher organisms, yet in none more firmly established, nor more conclu- 

 sively settled, and that by direct observation, than in some of the lower 

 Algae, which, by reason of their simple structure, range themselves 

 (along with the Conjugatae) in the group of Confervoideae. It may be 

 urged, indeed, that the conjugating cells show no so great differentiation 

 either in organization, dimensions, or appearance, as do the spermato- 

 2oids of those Algae in which they have been discovered, from the germ- 

 cells which it is their function to fertilize. This to a large extent is 

 granted ; but, nevertheless, a certain amount of specialization of certain 

 conjugating cells in some forms does occur, pointing to something more 

 than a mere fusion, without any significance. Indeed, the conditions 

 which accompany conjugation in the different forms present a series, in 

 their way, almost as varied as do the germ-cells and speimatozoids of 

 other Algae — not so pronounced, it is true, but still pointing, I think, to 

 an analogy. 



It will be proper, in pursuance of the argument, to advert to some 

 of the varied examples ; but, in the first place, it will be advisable briefly 

 to draw attention to certain cases where a true fertilization has been 

 proved in other Families, and then to compare that act and its results 

 with some of the Conjugatae. 



In Vaucheria there exists a large globose germ- cell, and exceed- 

 ingly minute, very numerous elongate spermatozoids, both elements of 

 the fructification originating in neighbouring specially formed branches 

 of the tubular filament, these not distinguishable at their first com- 

 mencement from one another, or indeed from ordinary branches, though 

 afterwards so highly differentiated. Here the difference in form and 

 size between the germ- and sperm-cell is very great, and the resultant 

 spore developes directly into a new plant. The difference of opinion 

 between observers (Karsten,f Pringsheim,^: Dippel§) as to the modus ope- 

 randi of the fertilization in this genus does not seem to bear on the imme- 



* " Quarterly Journal of Microscopical Science," N. S., vol. i., p. 18. 

 f Karsten, in " Botanische Zeitung," x., p. 85 (1852). 

 j Pringshciui, in "Berichte der Berl. Akademie." 



§ Dippel, "Ueber die Fortpflanzung der Vaucheria sessilis" in " Flora," 1856, 

 pp. 481,497. 



