NOTES AND MEMOKANDA. 4i9 



zoosporauges, with all their consequences, such as root-cells, 

 &c., or they may be directly modified into hypnosporanges. 

 But they can also carry on existence in yet another way. 



If exposed to drought the following series of phenomena 

 may be observed : — The wall collapses more or less, and the 

 protoplasmic chlorophyll-bearing contents break up into a 

 number of cells, their number depending on the size of the 

 mother-plant. Each is surrounded by a delicate membrane, 

 its contents homogeneous, at first green, with time and con- 

 tinued dryness or sunshine passing into red. These are 

 the spores of Botrydium, and have been known as Protococcus 

 coccoma, paliistris and hotryoides. 



These spores, be they green or red, become changed in 

 water to zoosporangia, their protoplasmic contents giving 

 rise to zoospores in the Avay already described. If the 

 spores be still green, their zoospores have a distinct fusiform 

 figure. At the apex of the shorter end they possess two 

 cilia. They consist of protoplasm which is slightly coloured, 

 with exception of a lenticular-shaped region, stretching at 

 one side a certain distance backwards, which remains un- 

 coloured. These zoospores conjugate in twos, sometimes 

 several together. They come in contact by their ciliated 

 ends, then come to touch laterally by the uncoloured portions, 

 when the fusion of the conjugating zoospores takes place, 

 immediately after which they present a cordate figure, and 

 in the middle is noticeable a colourless vacuole. Finally 

 the isospore thus originating becomes globular, the vacuole 

 occupying the centre. 



If the zoospores be isolated before conjugation, they finally 

 break up, Avithout presenting any products capable of ger- 

 mination. 



The zoospores, likewise sexual, originating from the red 

 spores, have a different figure, their posterior end being 

 rounded off; otherwise they have the same structure, and 

 behave, as regards conjugation, in the same way as the 

 green ones. 



The red spores maintain their germinative powers for 

 years, but after two years their zoospores are languid and, 

 what is more important, they offer a parthenogenesis of a 

 peculiar kind. The red spores, if they be kept moist only, 

 become no more altered even after weeks, whilst the green, 

 under these circumstances (as already pointed out by Cien- 

 kowski), may directly germinate into vegetative plants. 

 Whether these present ordinary or sexual zoospores the 

 authors did not follow out. 



To return to the isospore. It is at first globular and 



