254 Dr. L. Radlkofer on Fecundation in the Vegetable Kingdom^ 



jection on the wall of the main tube. It was not difficult to 

 find, after a little search, some which gave signs that the act of 

 fecundation might be immediately expected, — that is, sporanges 

 in which the orifice for the entrance of the spermatozoids was 

 already formed at the apex, while the neighbouring horn was 

 still perfect. I isolated several of the filaments so developed, 

 and carefully covered those which appeared ripest with a piece of 

 thin glass, in order to trace their further development under the 

 microscope. The pressure of the cover was even too much for 

 the antheridia which were near bursting. They opened, and I saw 

 the greater part of their mucous contents exude with a sudden 

 jerk. A quantity of short spindle-shaped corpuscles escaped 

 from this, and moved about in the water by means of cilia 

 vibrating like a whip-lash (whether each corpuscle bore one or 

 two — and, indeed, as it appeared to me in several, one at each 

 end of the body — I could not make out with certainty) . I saw 

 but few, as compared with the total number, penetrate into the 

 open beak of the sporange, and there perform the movement of 

 crowding against the mass of protoplasm as described by Prings- 

 heim. Whether any of them actually penetrated into this, I could 

 not certainly ascertain. Pringsheim, indeed, has not directly 

 observed the penetration of the spermatozoids into the mass of 

 protoplasm ; he rather concludes it, from the subsequent detec- 

 tion of a colourless corpuscle inside the new cell-membrane. 



In the germination of the resting-spore of Vaucheria, the in- 

 most layer of its membrane is directly developed into the thallus- 

 filament*. 



Pringsheim has demonstrated the existence of at least the 

 micropyles of the sporanges, in which the resting-spores ori- 

 ginate, in a number of other freshwater Algae, — for example, in 

 Achlya prolifera, where they exist in numbers probably equal to 

 that of the spores formed in each sporange t; in (Edogonium 

 and Bulbochcete, And his observations render it probable that 

 the microgonidia first described by Alex. Braun J, and shown to 

 exist in various families of freshwater Algse, which in Bulbochate 

 and (Edogonium attach themselves upon the sporangium or in 

 its immediate neighbourhood §, and discharge their contents 

 either immediately or after forming a few cells — are to be re- 

 garded as antheridia. 



* Pringsheim, I. c. p. 12. 



t Thuret represented them in the masterly drawings accompanying his 

 *' Memoir on the Zoospores of Algaj," but he regarded them as httle lids. 

 Ann. des Sc. nat. 3 seCr. xiv. p. 23l. pi. 20. iig. 11 (1850). 



X Alex. Braun, 'Verjiingung' (Ray Soc. vol. 1851, p. 1.'37). 



§ As observed also by De Bary, and figured in his essay " On (Edorjonium 

 and Bulhochate," Abhandl. der" Senkenberg. Naturf. Gesellsch. i. pi. 3&4. 

 (Frankfort-on-Maine, 1854.) 



