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



the antheridia of tlie Cryptogamia*, Thuret assumed the active 

 2-cihated coi-puscles contained in the above-mentioned cells to be 

 spermatozoa, on account of their not germinating; more recently t, 

 he has given proof of the correctness of his hypothesis by ex- 

 periments on dioecious species oiFucus, showing that where these 

 bodies are excluded, the spores remain incapable of germination, 

 i. e. unfecundated. According to his account, the spores (sporules 

 of authors) are formed in eights, fours, twos, or only one, in 

 the unicellular sporangcs, which have a smaller cell forming a 

 pedicle to attach them to the wall of the conceptacle. These 

 spores emerge from the sporange as primordial cells, as yet un- 

 enclosed by a proper membrane, but surrounded by a common 

 envelope (and thus hitherto regarded by authors as single 8- &c. 

 parted spores, octospores, &c.), from which they are immediately 

 set quite free, and come in contact with the spermatozoa. The 

 author could not detect a material penetration of the spermatozoa 

 into the spore-mass. Soon after fecundation J the spore becomes 

 clothed by a cell-membrane, and then is developed into the 

 young plant. 



Pringsheim§ confirmed Thuret's statements. The only dif- 

 ference is, that Priugsheim thinks the spermatozoids actually 

 penetrate into the membraneless spore-mass, and are immediately 

 enclosed by the new cell-membranes. He was led to this opinion 

 by observing a number of small red-brown nuclei inside the 

 spore-membrane, which were not present before the fecundation, 

 and appeared to him to be the remains of the spermatozoids, 

 which are furnished with a red nucleus. 



^yith regard to the other sections of the Fucoidese, spermato- 

 zoids have been described by Thuret 1| in Cufleria, by Pringsheim 

 in Sphacelaria and Cladostephus^ . The structure of the antheri- 

 dia is different in these plants. 



In the Floridese peculiar organs have likewise been long 

 known, which the first observers, although without sufficient 

 reasons, explained as antheridia. This was the case with C. 

 Agardh. Lyngbye regarded them as an animal structure; 

 J. Agardh as a hypertrophic metamorphosis of the ordinary 

 organs of propagation ; Kiitzing** applied to them the name of 

 ' spermatoidia,' considering them as seed-like accessory struc- 



* Ann. dcs Sc. nat. 3 ser. xvi. p. 5 (1851). 

 t Ibid. 4 SIT. ii. p. 19? (1854) 



, ^„.„. . ^- ,-. -. , ^-^., ._,. 



X Thuret, Memoires tie la Soc. Imp. de Cherbourg, v. Ajiril 1857. 



§ Pringsheim, Ueb. d. Befruchtung u. Kcimung der Algen. In'rlin, 



.55, p. 12 et seq. (Annals, 2 ser. xiv. /. c.) 



II Ann. des Sc. nat. 3 ser. p. 12 (1851). 



•^ Ueb. Befrucht. dor Algen. Berlin, 1855, pp. 21, 23. 



** Phycologia generalis, pp. 107-10.9 (1843). 



