60 



Chlorophycece 



which contains much chlorophyll. The antheridia may be developed 

 in the same filament as the oogonia, as in the monoecious species 



(fig. 12), or they may 

 arise in separate male 

 filaments, as in the dioe- 

 cious species (figs. 13 and 

 14). The antheridia are 

 sometimes unicellular, 

 consisting of a short cell 

 rather narrower than the 

 ordinary vegetative cell 

 and containing less chlo- 

 rophyll. More frequently, 

 however, they consist of 

 more than one cell, and 

 occasionally of a dozen or 

 more, the contents of each 

 antheridial cell dividing 

 into two masses each of 

 which becomes an anther- 

 ozoid. Rarely only one 

 antherozoid is produced 

 in an antheridial cell. The 

 antherozoids are similar 

 in form to the zoogonidia 

 and are ciliated in the 

 same way, but they are 

 smaller and contain less 

 chlorophyll. 



Dioecious species in 

 which the male filaments 



Fig. 12. Monoecious species of CEdogonium. 

 A, a form of CE. obsoletum Wittr., from near 



Goring, Oxfordshire. B, CE. zig-zag Cleve var. are } ar g e an( J but little 



robustum West & G. S. West, from Harefield, 

 Middlesex. C, CE. Itzigsohnii De Bary var. minor 

 West, from the Orkney Is. D, CE. Ahlstrandii 

 Wittr., from Pilmoor, N. Yorkshire (x460). 

 oo, oogonium ; a, antheridium. 



inferior in size to the 

 female filaments are said 

 to be dioecious macran- 

 drous (fig. 13). 



There is, however, another type of dioecious species in which the 

 male plants are very small and are attached to the female plants ; 

 these are said to be dioecious nannandrous (fig. 14). This type 

 requires a further description. Certain short cells are produced in 



