268 THE .PHENOMENON OF 



Cladophora, and probably also of ChaetomorpJia (p. 185), 

 agrees essentially with the mode of cell-formation here de- 

 scribed; moreover, judging from the statements of authors, 

 those of Endococcus (Nageli, 'Einz. Algen./ p. 17) and 

 Bryopsis, in which genus the accurate tracing of the pro- 

 cess, especially in reference to the behaviour of the chloro- 

 phyll vesicles, would be especially important. The formation 

 of the gonidia, as well as the spores, of Saprolegnia, 

 likewise referring here, deserve a more minute exami- 

 nation, on account of their somewhat aberrant character. 

 The apices of the filaments, swelling up into longish clubs 

 or cylinders, and becoming shut off as separate cells, in 

 which the gonidia of Saprolegnia are formed,* are filled 

 at their formation with a granular mucilage. Subsequently 

 several cavities present themselves in the interior of the 

 mucilaginous mass, along the axis of the club, which 

 cavities, gradually increasing in size, become blended 

 into a single cavity traversing the entire tube, not, how- 

 ever, of very large size. The contents thus converted 

 into a thick parietal mucilaginous layer, soon acquire an 

 undulated surface, forming little rounded eminences, 

 which project more and more, while the intermediate 

 furrows continually cut in deeper until they at length 

 reach the cell-wall. In this manner the mucilaginous 

 layer becomes divided into numerous hemispheres, at- 

 tached by their flat sides upon the cell-wall; these, 

 however, immediately become rounded into globules, 

 separating simultaneously from the cell-wall. This com- 

 pletes the formation of the gonidia, which immediately 

 commence their movement, continuing it for some time 

 after they have been expelled from the mother-tube. 



* The formation of free sporangia in the interior of the swollen points of 

 le filaments, described and figured by Niige' 1 ' f ' ^.VenK,. > i a/i.7 v 

 t. iv, figs. 1 6,) is totally different from this. 



the filaments, described and figured by Niigeli, (' Zeitschr.,' 1847, p. 28, 

 t. iv, figs. 1 6,) is totally different from this. I have likewise seen it, so 

 rarely, however, that I could not trace the whole course. It seemed to me 



not to belong to the sphere of the normal phenomena of development of 

 Saprolegnia, and is just as enigmatical as the occurrence of sessile globular 

 excrescences with rotating and subsequently rcpeaiedly dividing contents, 

 observed iu the same plant. 



