126 PRINGSHEIM, ON THE IMPREGNATION 



acquires a meml)rane, and thus comes to represent the vege- 

 table embryonic cell capable of immediate development. 



The parent-spore in Fumis and the sporangium in Vaucheria, 

 are morphologically equivalent to the central cell of the arclie- 

 qonium in Ferns and Mosses, to which the canal of that organ 

 leads, and to the embryo-sac of phanerogamous plants. The 

 author has hitherto in vain sought for an embryonic cell before 

 impregnation has taken place, in the central cell of the arche- 

 qonia. But, on the contrary, is pretty well convinced that in 

 this case also the true embryonic cell is not formed around a 

 portion of the contents of the central cell until after the en- 

 trance of the spermatozoids, and that it encloses the sperma- 

 tozoids which have thus effected their entrance. May not 

 the same process take place also in phanerogamous plants ? 

 May not the point of the pollen-tube which enters the embryo- 

 sac enclose the spermatozoids, which together with the contents 

 of the embryo-sac become the cell of the embryo, which is not 

 developed until after impregnation ? 



After noticing the obvious analogies, thus indicated, between 

 the process of impregnation and the probable mode of origin 

 of the first embryonic cell in animals and plants, the author 

 goes on to speak of the sexual organs in the Floridece. 



He says that his own observations, which fully agree with 

 those of Thuret, Mettenius, Derbes, and Solier, show that 

 Nageli was in error in stating that the antheridia, or cells so 

 termed in the Floridece^ contained spiral filaments. These 

 organs, however, ai'e nevertheless true antheridia, and the 

 absence of spiral filaments in them only show what was evident 

 in Fucus and Vaucheria, that the existence of spiral filaments 

 can no longer be regarded as the sole morphological proof of 

 the male function of an organ. On the contrary, it is indis- 

 putable that there are several forms of self-moving corpuscles 

 which, in plants, exercise the function of spermatozoa. 



Besides the spermatozoids of the Ferns, Mosses, Characeae, 

 <Scc., which approach in conformation the animal spermatoza, 

 we are at present also acquainted with forms more nearly 

 approaching zoospores, as in the Fucacece ; and, lastly, with 

 that, differing from either, peculiar to the spermatozoids of 

 Vaucheria, whose nearest allies would perhaps be met with 

 among the Lichens. But the cells of the so-termed antheridia 

 of the Floridece, manifestly resemble in the most striking 

 manner the spermatozoids of the Fucacece, and still more those 

 discovered by the author in Sphacelaria, which, in their struc- 

 ture, appear to constitute an intermediate form between the 

 two. This correspondence in structure, renders it in the 

 highest degree probable that these organs constitute the true 



