SPIROGYRA : VATJCHERIA. 



269 



starch which is later replaced by oil-drops, the chlorophyll 

 being more or less replaced by red pigment. 



These filaments may also show, if kept tinder obser- 

 vation, that when the zygospore germinates the thick outer 



Fig. 57. SPIKOOYRA. Stages in conjugation. See 384. 



coats are ruptured, and the protoplasm (covered by the 

 thin inner coat) grows out as a tube divided into two cells, 

 of which the upper is green and developes into the 

 filament, while the lower cell (covered by the spore-coat) 

 is colourless and soon disappears. 



VATJCHERIA. 



385. Occurrence. Most of the species of Vaucheria 

 grow in fresh water, or on moist soil or mud in ditches, 

 but some live in the sea or in brackish water in estuaries 

 and salt marshes. A convenient species for study is V. 



