72 Peridinieae 



observed, coincides with observations on mutations in other organisms, and 



I 



Fig. 52. Normal chain of Ceratium vultur 

 Cleve, twisted at the fifth cell from the rear, 

 showing ventral view anteriorly, and dorsal 

 view posteriorly. x 100 (after Kofoid). 



Fig. 53. Mutating chain of Ceratium. The 

 posterior cell (IV) is C. tripos (0. F. M.) 

 Nitzsch, and cells I III are C. californiense 

 Kofoid. at.a., attachment area; ch.ch., 

 chain channel; fl.p., flagellar pore; v.a., 

 ventral area covered by so-called ' ventral 

 plate.' x 430 (modified from Kofoid). 



the instances of their occurrence suggest the influence of environmental 

 factors in producing the mutations. 



