Fig. 



Fig. 



Fig. 

 anterior 

 X 1000. 



Fig. 



Fig. 

 X 1000. 



PLATE 12 



Gonyaulax poJyedra Stein 

 All specimens from San Diego, June, 1904. 



16. Dorsal view of theca showing plates. X 1000. 



17. Ventral view of same. X 1000. 



18. Ventral view of recently divided theca, showing unmarked 

 moiety and porulate posterior one and the fission line (/'. /.) 



19. Antapical view of hypotheca. XI 000. 



20. Apical view of epitheca with normal type of apical plates. 



1-6 — girdle series of plates. 

 l'-4' — apical series. 

 1(1-^(1. — anterior intercalary plates. 

 1"-6" — precingular series. 

 1'1'^Q"' — postcingular series. 

 IP — posterior intercalary plate. 

 1"" — antapical plate. 

 'int. pi. — anterior plate of ventral 

 area. 



ABBREVIATIONS 



cJ. pJ. — closing platelet of apex. 

 /'. I. — fission line. 

 /?. po. — flagellar pore. 

 int. pi. — intermediate plate of ven- 

 tral area. 

 post. pi. — posterior plate of same. 

 V. po. — ventral pore. 



Figures 16. 17, 19, and 20 drawn by Mr. D. B. Billinghurst, figure 18 

 by Mrs. Josephine Rigden Michener. 



[276] 



