1 



262 TJniversit\j of California Publications in Zoology. ["Vol. 8 



apical or anterior intercalary plate to the right of the mid- 

 ventral line. 



4. The ventral area or true longitudinal furrow consists of an 

 anterior plate indenting the epitheca and bearing on its post- 

 margin the flagellar pore; and an intermediate region of two to 

 four small plates, and a large posterior plate. 



5. The fission line in dividing theeae is described. 



6. The genus is revised, twenty-five species being recognized, 

 fourteen recorded from coasts of California, and four new ones, 

 G. alaskensis, G. diegensis, G. scrippsae, G. sphaeroidea de- 

 scribed. The synonomy, variation and distribution of each is 

 discussed. 



7. The all-pervading character of specific differences in both 

 morphological and physiological details is described. 



8. The apical region and ventral area, regions coming most 

 in contact with the environment are most subject to diversi- 

 fication. 



Zoological Laboratory , University of California. 

 Transmitted May 10, 1911. 



