GROUP I. THALLOPHYTA : ALGM : CHLOROPHYCEJJ. 239 



whole protoplasm of the body, in the latter from that of successive branches of 



FIG. 109. Vauchena sessilis (x 30). A sp A newly-formed zoogonidium. B A resting 

 zoogonidium. C, The commencement, D and E more advanced stages, of germination ; 

 sp zoogonidium; s apex of the green filament; 10 a colourless adventitious root. F Fila- 

 ment with sexual organs ; og oogonium ; 7i antheridium after rupture. (After Sachs.) 



FIG. 170. Acetabulavia crenulata, (after Kiitz- 

 ing; nat. size): the terminal circular disc con- 

 sists of a whorl of coherent leaves; in these 

 the gametangia are formed. 



FIG. 171. Botrydium granulatum 

 ( x 6) : s the green shoot ; w the 

 colourless root. 



