ECOLOGY AND TAXONOMY OF Holimeda 



207 



Fig. 67. H. incrussata. Section through \ciy dark green gametangiuni fixed about 

 12—16 hours before the estimated time of discharge of gametes, showing gametes 

 with mitochondria, chloroplast with starch (only partly shown), apical papilla with 

 flagellum (second flagellum not m plane of sectioning). Also shown are long and 

 oblique sections of flagella. Cleavage has not been completed, and the two micro- 

 gametes are attached by a narrow bridge. Gametes were also observed joined in 

 threes. Stained with lead tartrate. Scale bar is 1 ^m. 



younger gametangia and the filaments of the segment. Not all the 

 cytoplasm is incorporated into the gametes. 



I have followed the discharge of gametes, which in my laboratory 

 cultures have been predominantly microgametes. Release occurs about 



