438 University of California Publications in Zoology [Vol. 22 



so at forty meters, whereas in 1921, at Station I, there was a slightly 

 larger number at twenty meters than at the surface. A few supple- 

 mentary catches at intermediate levels (tables 2 and 3) strengthen 

 the indication that production in the 1922 series was greatest near 

 or above the twenty meter level, and seldom great below the thirty 

 meter level (see also figs. 1 and 2, Station I and Station II). 



In September, 1922, the conditions were different in another way. 

 The total population of diatoms was small, being most numerous, on 

 the average, at forty meters at both stations. At Station I dino- 

 flagellates were taken in larger numbers at forty meters, although at 



TABLE 2 



Diatoms 



Miscellaneous depths. Numbers per liter. 



Station I Station II 



594 



10 2,520 826 ),M\ 



15 



20 8,736 2,296 1,012 15,960 360,:'.22 2,068 



25 



30 



35 



40 7,208 966 3,498 3,822 65,814 3,300 



50 



55 



Station II the most were found at the surface, as in 1921. The record 

 of the averages for both May -June and September (table 1) gives 

 a fairly good idea of the trend in the whole series of catches in 1922. 

 In both May-June and September the average numbers caught, 

 of both diatoms and dinoflagellates, were greater at Station II than 

 at Station I at all levels (table 1). Unpublished results of chemical 

 studies at the two stations (made by E. G. Moberg) show little differ- 

 ence except that hydrogen ion concentration is slightly lower at five 

 miles than it is at ten. Laeking information as to other influences, 

 mic is immediately pointed to the conclusion that Station II (five 

 miles out) was more favored by organic content of the water or other 

 shore effects than was Station I (ten miles out). This conclusion, 

 however, in spite of its ease of application should remain open to 

 question until more firmly established. Indeed, its application is 



