Fig. 7. Edogonium nodosum, a Conferva form ; A, portion of a filament showing a 

 vegetative cell with its nucleus {d\ an oogonium {a) filled by an egg packed with 

 food material, a second oogonium (c) containing a fertilized egg or oospore as 

 shown by the heavy wall, and two antheridia (6), each containing two sperms; B, 

 another filament showing antheridia {a) from which two sperms (6) have escaped, 

 a vegetative ceil with its nucleus, and an oogonium which a sperm (c) has entered 

 and is coming in contact with the egg whose nucleus (d) may be seen; O, a zoo- 

 spore which has been formed in a vegetative cell, showing the crown of cilia and 

 the clear apes, as in the sperms; I), a zoospore producing a new filament, puttmg 

 out a holdfast at base and elongating; M, a further stage of development; F, the 

 four zoospores formed by the oospore when it germinates.— Caldwell, except 

 (7 and F, which are after Pbingshbim. 



