440 



University of California Publications in Zoology [Vol. 22 



tribution of species, weight should be given to the fact that counts 

 are made under relatively low magnification and segregation of 

 species is very imperfect. It will be interesting to see if further 

 studies support or contradict the evidence just stated. 



TABLE 3 



DlNOFLAGELLATES 



Miscellaneous depths. Numbers per liter. 

 Station I S 



A total of fifty-two species of diatoms was provisionally recorded 

 (see Allen, 1923, p. 77) for the combined series. Of these, only ten 

 (exclusive of the catch-all assemblage, Chaetoceras sp.) reached prom- 

 inence sufficient to give them a place in the first five at either station 

 or any level. Of the ten, only one, Nitzschia seriata CI., was included 

 in the first five at all levels at both stations in May-June. In Sep- 

 tember it was missing at the ten mile station at the surface and at 

 twenty meters, although present at forty meters and at all levels at 

 the other station. Chaetoceras debile CI. (including Ch. curvisetum 

 CI.) was in the first five in May- June in all cases except the forty 

 meter level at Station I, where it was sixth. In September it was 

 prominent only at forty meters at Station II, corresponding very 

 closely in occurrence with Nitzschia seriata CI. 



Chaetoceras criophilum Castr. was among the five most prominent 

 at the twenty and forty meter levels at both stations in May-June, 

 but it was either absent or not conspicuous at other times. Eueampia 

 zoodiacus Ehr. was most peculiar of all in that it was taken very few 

 times at these stations but in very large numbers in three catches 



