352 Dr. L. Radlkofer on Fecundation in the Vegetable Kingdom, 



As a rule*, only one archegonium becomes further developed. 

 The cell just described increases iu size, until it fills the central 

 cell, and is converted by repeated divisions into a multicellular, 

 ellipsoidal body lying in the cavity of the archegonium, forming 

 thus the rudiment of the new plant — the prim ari/, never-developed 

 emhryonal axis. In the course of further growth, its point gra- 

 dually acquires rather intimate adhesion to the cells of the base 

 of the archegonium. Beneath the point, at the anterior side, 

 turned towards the younger, cordately-uotched border of the 

 prothallium, sprouts out the first frond, soon breaking through 

 the archegonium and curving upwards. Opposite this, from the 

 side next the older part of the prothallium bearing the antheridia 

 and radical hairs, arises the first adventitious root. The main 

 (axial) root, the lower end of the ovate embryo, remains un- 

 developed. Between the first frond and the permanently un- 

 developed point of the embryo soon arises, as a little cellular 

 papilla, the secondary, developing axis of the new plant, which 

 continually throws out new fronds from beneath its apex. 



On abortive prothallia, which under favourable circumstances 

 continue to vegetate for a long time, new archegonia arc suc- 

 cessively developed, but of different shape, wanting the elongated 

 neck ; they were regarded by Suminski and iMercklin as younger 

 stages of development of the archegonia. In addition to these, 

 there occur numerous shoots bearing abundance of unicellular 

 antheridia. 



Lcszczyc-Suminski and Mercklinf have observed the entrance 

 of the spermatozoa into the canal of the archegonia. The account, 

 long ago and generally refuted, given by the former, of the 

 origin of the embryo from the end of a spermatozoid which had 

 entered into the central cell of the archegonium — arising from 

 confounding the coagulated protoplasm of the archegonial canal 

 with a spermatozoid — requires no further notice. Even !Mercklin 

 modified Suminski's statements, saying that the spiral filaments 

 which penetrated the archegonium "here dispose a cell (through 

 dynamic or material action ?) to development under definite laws 



becomes either abortive or further developed, Hofiueister, Wigand, Merek- 

 lin, and Sumiuski are agreed ; Pringsheim, on the contrary, states that 

 here, as iu the Mosses, he couhl not detect it at this time as a cell {vide 

 op. cit.). With him accords Heufrey, if we properly connect his compa- 

 rison of the said structure with the germinal vesicles of the Phanerogamia 

 (Linn. Trans, xxi. p. 125), and his opinion, subsequently to be mentioned, 

 that these germinal vesicles possess no membrane before fecundation, but 

 are mere masses of protoplasm. 



* Exceptional cases were observed by ilercklin and Wigand {vide op. 

 cit. supra). 



t Vide op. cit. supra, and Mercklin, OflPeutl. Briefe an H. Schacht, ' Lin- 

 nsea,' xxiii. p. 732, 



