1918] Barrows: Skeletal Variations in the Genus Peridinium -125 



Fig. 19. — Diagrams of the arrangement of plates in a typical member of 

 the genus Peridinmm, P. divergens Ehrbg., for the epitheca (upper figure) and 

 for the hypotheca (lower figure). The epitheca! plate pattern is that of the 

 subgenus Metaperidinium, primary division. 



