THE VEGETABLE CELL. 115 



a globular lump in tlie middle. A " swarming " now begin^. to be 

 evident in this mass, the granules become isolated, and swim 

 about the cavity of the cell. A papilliform protuberance is after- 

 wards produced from the cell- wall, wliich tears at its apex, and 

 the spores making their way out by tliis orifice swim about in the 

 surrounding water. By degrees they begin to withdiaw towards 

 the darkest part of the water, become attached to any solid body, 

 and begin to germinate, by an expansion of their membrane. 

 A2:ardh observed a transparent process (beak, Schnabel) at that 

 en^d of theBe spore, wldf .Iwa^s went' first' in the mLznents. 

 But the true organ, on which this movement depends, is not this 

 beak, which itself is motionless, but, as Thuret fir^t shewed 

 (''Ann. d, Sc. nat sec. 8er/' xix. 266), there exist at the brighter 

 coloured end of the spore, cili^ of various lengths moving rapidly, 

 and by their vibrations causing the motion of the whole spoi^e. 

 The number of these ciliae differs in different genera. Thuret 

 found in Conferva glomerata (see tab. 1, 23, 24,) and Twularis, 

 two cilise on each spore, in Ghoetophora elegans four, on the spores 

 of Prolifera a circle of very numerous cili^, (see tab. 1, 19 — 22, 

 which represent the spore (19) and its first stages of develop- 

 ment, after Thuret); subsequently (''Ann. cL 8g, nat Sme. Serf 

 iii 274) he made known that the spores of Ectocarpus have two, 

 those of Ulva and Enteromorpha four ciliss. These observations 

 obtained full confirmation by othei*s, especially by Fresenius 

 ("Zur Gontrov^ UK die VerwandL von Infus. in AlgenJ, and by 

 Alex. Braun (repeated by Siebold, ''^An7h. d. 8c. nat Sme. Ser, 

 xii 151). The opinion that these spores possess animal life during 

 the period of their movement, and become plants at the moment 

 of germination, does not, however, depend merely on a confusion 

 of their movements with the voluntary motion of animals^ but 

 derives an apparent confirmation fi^om the fact that in very many 

 cases each of these spores contains a red spot (according to Nageli 

 a red oil-dxop), which was taken for an eye by Ehrenberg and 

 others. Even before Thuret had made known his observations 

 upon the organs of motion of the zoospores, Unger ("Die Pjianze 

 im Momente der Thier-werdung") had published very minute 

 observations upon the formation and motion of the very large 

 spores of Vaucheria. In Vaticheria^ the single granules of chlo- 

 rophyll are not developed into minute spores famished with a few 

 cilise, but the entire mass of chlorophyll of the terminal joint of a 

 filament, or of globular protuberances seated upon lateral branches, 

 after being separated from the contents of the rest of the fibre 

 by a septum, becomes balled together into one common spore, 

 which makes its way out by a slit in the cell-membrane and ex- 

 hibits rapid advancing and twisting movement. It is covered 

 all over with countless vexy short eilise. The whole of the forma- 

 tion of the spore occurs early in the morning, its exit from the 

 parent-cell usually takes place about 8 A M., and after its motion 



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