THE BEGINNINGS OF LIFE. 177 



day. Dr. Hassall says : c The tufts which I have 

 gathered the day before, and which presented no indi- 

 cation of the formation being near at hand, were in 

 general covered with spores the next morning- and 

 after midday these were all gathered on the surface 

 of the water beginning to germinate.' 



The mode of origin of the so-called c resting spore ' 

 or c seed-cell 1 ' in (Edogcnium is also very interesting, 

 and illustrates in an important manner the question 

 we are now considering. In this case, the whole of 

 the protoplasmic contents of one of the cells of the 

 plant goes to produce a single new reproductive ele- 

 ment, instead of many as in the case of Conferva 

 area. Alexander Braun - describes the changes which 

 take place as follows : c In the formation of the rest- 

 ing seed-cells of QEdogonium we see the thickish cell- 

 contents composed of greenish coloured mucilage, 

 mixed with chlorophyll and starch vesicles, which, in 

 the earlier vegetative period of the cell, form a lining 



1 These are reproductive products which do not develope immedi- 

 ately after they have been formed, into the plant which they may ulti- 

 mately produce. They continue, as Braun says, ' for a long time in a 

 condition of rest, during which, excepting as regards imperceptible 

 internal processes, they remain wholly unchanged.' The direct germ- 

 cells, or swarming-spores (gonidia, or zoospores), however, pass on, 

 after their evolution, through a continuous process of growth and de- 

 velopment till the perfect plant is reproduced. These latter are the bodies 

 of which we have already spoken in connection with Conferva area, and 

 of whose development in Achlya prolifera we are shortly about to speak. 



2 ' Rejuvenescence in Nature ' (Translation by Henfrey, Ray Society), 

 1853, p. 164. 



VOL. I. N 



