34 SURVEY OF THE REPRODUCTIVE PROCESS 



to be absorbed. The mass then acquires a membrane of 

 cellulose on its exterior, and becomes a true spore.* 



In CEdogoniiim, Btdhochocte, and Coleochwte a process has 

 also been observed during the germination of the spore, 

 which might be termed one of protomorphic gemmation. "I* 

 In these, and perhaps also in some other genera, the spore 

 does not germinate at once into a new frond, as in other 

 Algae (Aclilya, Vaucheria, (&(;.j but becomes converted into 

 a sort of capsule containing four bodies, precisely resembling 

 the ordinary zoospores of the plant in their appearance, 

 their motion, and their power of germinating into new 

 fronds. 



The genus Vaucheria may be taken as the type of an- 

 other family ofconfervoid Algse — the Siphoneae — which are 

 sometimes described as unicellular, the filaments having no 

 tranverse septa. The sporangia commence as lateral 

 diverticula, but are afterwards shut off as separate cells. 

 The antheridium originates as a papilla, in close proximity 

 to the sporangial dilatation, and generally precedes it a 

 little in its first development. It ultimately acquires the 

 form of a hooked process, or abortive tendril (" hornlet"), 

 curving over the sporangium. The point of the hornlet is 

 soon converted into a separate cell, and its contents, which 

 had previously become colourless, are then resolved into 

 antherozoids. Perforations taking place subsequently, both 

 at the point of the hornlet, and at the most prominent part 

 of the sporangium, the antherozoids come in contact with 



* Pringslieim's Report to tlie Berlin Academy. See Quarterly Journal 

 of Microse. Science, IV., 131, andEdinb. PLilosopliical Journal, N.S. V., 

 376 (1857). In the species of CEdogonium observed by Mr Carter the 

 antherozoids were not formed in free androspores, but were emitted di- 

 rectly by peculiar short cells, grouped in pairs or clusters of three, and 

 giving a ringed appearance to certain parts of the filament. Ann. Nat. 

 Hist., 2d Ser., XVIII., 81, and 3d Ser., I., 19. 



t Edinburgh Philosoph. Journal, V., 376 (1857). Quarterly Journal of 

 'Microscopic Science, IV., 133. 



