258 



PROTOZOOLOGY 



brown; stigma usually present; cysts spherical; salt or fresh water. 

 Numerous species. 



P. tahulatum Claparede and Lachmann (Fig. 110, c). 48m by 44^; 

 fresh water. 



Fig. 110. a, b, Pohjkrikos kofoidi (a, colony of four individuals, X340; 

 b, a nematocyst, X1040) (Kofoid and Swezy); c, Peridinium tahulatum, 

 X460 (Schilling); d, P. divergens, X340 (Calkins); e, Ceratiuni hirundi- 

 nella, X540 (Stein); f. C. longipes, XlOO (Wailes); g, C. tripos, Xl40 

 (Wailes); h, C. fusus, XlOO (Wailes); i, Heterodinium scrippsi, X570 

 (Kofoid and Adamson). 



