VOLVOCALES 



35 



dioecious, and after fusion has taken place the zygote divides into 

 four to eight aplanospores which later grow into new colonies. The 

 place of meiosis in the life cycle is not yet known. 



Chlorodendraceae : Prasinocladiis {prasino, leek-like ; cladus, shoot) 

 (Chlorodendron). Fig. 25. 



This genus is to be found principally in marine aquaria where it 

 starts life as a quadriflagellate swarmer of the chlamydomonad 



I 

 I 

 I 

 I 

 I 



I 

 I 

 I 

 I 



I 

 I 



Fig. 25. Prasinocladus. A, B, portion of plant showing cell structure, 1-3 = cells. 

 C, portion of plant showing arrangement of cells at branching. D, portion of 

 plant with branches and living cell. (All x 1600.) ^^^ = pyrenoid, n = nucleus, 

 5 = stigma, c = chloroplast, m = basal margin of terminal protoplast, 6r = first 

 branch, Z>ri = second branch, c/ii-c/z4 = short chambers behind terminal cell at 

 times of division, ch^ being the earliest, /= minute remnant of flagellae, c^, c^. 

 = bases of t^vo cells, ^ = papilla, = overlap of lateral wall, Z = entire lateral 

 extent of one chamber, e^ = papilla pointing upwards, 6c = basal cross wall, 

 ti, i2 = tops of two cells. (After Lambert.) 



type. The swarmer comes to rest and a new wall is formed with 

 papillae at the base. Then the apex of the old wall ruptures, and 

 when the contents have developed flagellae they move up, together 

 with the new wall, so that the new cell becomes enclosed in the neck 

 of the old one. The flagellae are lost for a time and then the process 

 is repeated, and in this manner a filament of dead cells is built up 



^-2 



