298 M. A. Braun on, the Nucleus of the Characeae. 



Bischoff in the year 1828*, who at that time regarded them as 

 Infusoria. Varley (1834) first saw their exit from the cells of 

 the antheridial filaments ; but the two most delicate cilia, by the 

 vibration of which the spirally wound body is set in motion, were 

 first described by Thuret in the year 1840t. Thui-et saw these 

 cilia in Nitella syncarpa and Chara fragilis ; I have seen them so 

 distinctly in Chara aspera and ce?'atophi/lla, that no doubt what- 

 ever can exist as to their presence. I laave only to add to Thu- 

 ret's account, that I have found the winding of the spiral body 

 constant to the riffht in Ch. fragilis. The second organ of fruc- 

 tification, in which the spore is developed, regarded by the older 

 botanists as a pistil, and in the ripe .condition called either 

 capsule (Vaillant), beri-y (Sprengel, Willdenow), drupe (Berto- 

 loni), or nucule (Wallroth), or merely seed (Linnaeus), has been 

 subsequently, quite as unfitly, termed a spore-case, sporocarp (Bis- 

 chofi^), or sporangium (Cosson and Germain). Hofmeister com- 

 pares it with the archegonium {pistillidium) . Apt as this compa- 

 rison seems in reference to the reduction of the characters of 

 fructification of all the higher (spermatozoid-beariug) Crypto- 

 gamia under one common point of view, since in this way all the 

 plants with unequivocal antheridia likewise possess an archego- 

 nium, peculiar difficulties are met with in the attempt to cany 

 out the parallel. That which has been called an archegonium, 

 is an organ of the first generation of the leafy Ciyptogamia, the 

 generation growing up from the spore, in which organ, accord- 

 ing to the researches so profoundly followed out by Hofmeister 

 in particular, the germ-cell of the second generation is produced 

 by free cell-formation, and developed after impregnation (like the 

 embryo of the Phanerogamia) . In the Vascular Cryptogamia 

 (Ferns, Equiseta, &c.) the first generation consists of a leafless, 

 thalloid preparatory structure, the pro-embryo or prothallium, 

 whUe the second generation is developed into the leaf-producing 

 ' stock,' the vegetative, and finally spore-bearing plant ; in the 

 Mosses, on the other hand, the first generation advances from 

 the thalloid preparatory structure to the leaf-producing ' stock,' 

 while the second generation is represented by a peculiar fruit- 

 structure serving merely for the production of the spores, and 

 this structure, emerging from the cavity of the archegonium, 

 sometimes breaks through the cover [calyptra) formed by the 

 latter, and sometimes can'ies it up through its becoming detached 

 below. In the lowest groups of Hepaticse, especially in the 

 Ricciete, this fruit-structure, so complicated in the higher Mosses, 



* Civpt. Gewachse, p. 13. in the note. 



t Ann. des Sc. Nat. 2nd ser. xiv. (1840), p. (IS ; and 3rd se'r. xvi. (1851), 

 t.9. 



