CRYPTOGAMS 



343 



lies in a transverse furrow (Fig. 268 A, <//). The protoplast contains a nucleus, 

 vacuoles of different sorts, and numerous brownish-yellow chromatophores ; the 

 latter contain a mixture of several special pigments (reddish-brown phycopyrin, 



schl 



in 



FIG. 208. A, Gymnodiniumrhomboides: If, longitudinal groove ; gf, transverse groove. B, Goniodoina 

 acuminatum : the flagella, which arise from the orifice gsp, are not represented ; schl, d, plates 

 of the wall ; g, girdle. C, Peridinivm tabulatum : h, wall. (A, B, After SCHUTT ; C, after 

 KLEBS ; from OLTMANN'S Algae.) 



red peridinin, and yellowish-green chlorophyllin). Oil is usually formed as the 

 product of assimilation. While the Gymnodineae (Fig. 268 A) have either naked 

 cells or cells limited by a uniformly thickened cellulose wall, the typical Peridineae 



Fin. 269. Peridineae from the plankton. A, Ornithocerctts splendidttg ( x 150). B, C, Species 

 of Ceratium ( x 125.) (After SCHOTT.) 



have a wall composed of cellulose formed of polygonal plates ; these are usually 

 delicately sculptured and perforated with pores. The transverse furrow is formed 

 by one girdle-shaped plate (Fig. 268 B}. 



