NOTES AND MEMORANDA. 447 



lapsed wall of the Botrydium. Such were known to pre- 

 vious observers as *' germ-cells " or "gonidia/' 



The zoospores are elongato-oviform, 5 — 8 mm. in breadth, 

 and about 20 mm. long. They are furnished with two to 

 four chlorophyll-granules, and hear, at the colourless, scarcely 

 pointed apex, a single long flagellum. 



Having once swarmed out they soon come to rest, lose the 

 flagellum, become surrounded by a membrane, increase in 

 size, and on damp earth soon germinate. 



This they do by giving off from the downward side a short 

 hyaline process, which penetrates the soil, the opposite end 

 becoming elevated upwards, and remaining the only bearer 

 of the chlorophyll. In this stage they represent the so-called 

 Protococcus hotryoides. 



Reverting to the large zoosporanges, which the authors 

 call ordmary, they found them capable of yet another modi- 

 fication. If one be allowed to dry, its membrane begins 

 to collapse, loses its colour in time, and becomes soon empty. 

 The membrane is covered by fine calcareous granules, is 

 dry, brittle, hyaline; the whole protoplasmic contents have 

 now passed down into the ramifications of the root. Here 

 they break up into a number of cells, all nearly alike, only in 

 the thicker neck-part they lie two or three side by side, 

 whilst elsewhere they present a continuous simple chain. 

 Each of these root-cells is surrounded by a special mem- 

 brane. 



These are capable of a threefold mode of development. 



If removed from the soil and brought into a drop of water 

 the membrane swells, bursts the wall of the root, and be- 

 comes a subterranean zoosporange ; the formation of the 

 zoospores is independent of the light at any hour of the day 

 or night. The zoospores are quite similar to those above 

 described, and in germinating behave in the same way. 



If a chain of these root-cells, still inclosed in a ramification 

 of the root itself, be laid on moist earth, they each put forth 

 a hyaline process, which presses into the soil, the opposite 

 end arising aloft, thus each root-cell becoming a vegetative 

 plant. 



But if the root-cells are not removed and the culture be kept 

 equably moist, in time another modification ensues ; they 

 now begin to germinate in the earth. They become inflated, 

 putting forth a hyaline root-process, the wall of which be- 

 comes very much thickened on the inner side below the in- 

 flated upper portion. This thickening advances almost to 

 the obliteration of the cell-cavity. By intercalary growth of 

 the root-portion the upper part becomes raised aloft, so that 



VOL. XVm. NEW SER. G G 



