140 THE PHENOMENON OF 



formation of gonidia seems to occur sometimes together 

 with the spore-formation, and this in a double way. The 

 formation of numerous small swarmers in unconjugated 

 cells is mentioned by Ralfs as a not uncommon phe- 

 nomenon, but in so indistinct a way, that we cannot form 

 a satisfactory idea of it.* 



The active corpuscles found by Ehrenberg in a 

 Closterium, which he described as monad-like Infusorial 

 animalcules, under the name of Bodo viridis,\ might be 

 referred here. 



According to Morren,| there is a totally different 

 pi'ocess in Closterium Lunula, where, through conjugation 

 of two individuals, a single large active germ-cell is 

 formed, which commences a revolving movement in the 

 connecting canal of the parent-cell, already inside the 

 coats, then leaves the torn coats, and, after swarming 

 from ten to twenty minutes, sinks down and immediately 

 germinates, i. e., becomes elongated and returns to the 

 form of the old Closterium. 



If these statements of Morren are correct, there occurs 

 in the Closteria a double character of the reproductive cells 

 formed through conjugation, these sometimes appearing 

 as direct germ-cells (gonidia), and sometimes as true seed- 

 cells, it being uncertain whether the two cases occur in 

 one and the same species, or separately in different 

 species. § The two- fold fructification of Vaucheria has 

 been spoken of already above (p. 128) ; it follows also, 

 from the observations of J. Agardh, || that large spores 

 are formed in addition to the small gonidia in Bryopsis. 

 Moreovei', the simultaneous occurrence of gonidia and 

 spores is beyond doubt, in the large genus OEdogonium 



* Ralfs, 'the British Desmidiece, p. 9. 



■)- Ehrenberg, ' Infusionsthierohen,' t. ii, f. 15. 



% Morren, 'Meinoire sur les Closteries.' ('Anii. des So. iiat.,' v, 1836.) 

 (See also Smith, 'Ann. Nat. Hist.,' 3d ser., vol. v, 1. — A. H.) 



§ It is remarkable that Ralfs, who has seen the formation of spores in so 

 many Desmidiacew, says nothing about it in reference to this very Closterium 

 Lunula, and the allied species CI. Ehrenbergii and nwniliferiim.. 



II .J. Agardh, ' Algw maris mediterranei' (1 S12), p. 4. 



