146 University of California Puhlications in Zoology. [Vol.8 



TABLE 54 



Vertical Distribution of S. serYatodentata based on Vertical Closing Net 



Hauls. 



It is significant that the data in both tables agree that this 

 species is mainly mesoplanktonic, and that the depth of maximum 

 abundance and frequency is below 150 fathoms. They disagree in 

 detail but, owing to very different methods of collecting, and of 

 different depths considered, this is to be expected. From the fact 

 that the frequency and abundance are more nearly parallel in 

 the former than in the latter table, the data in the former are 

 probably more reliable. 



In arranging the above data with respect to day and night, 

 the following table suggests that the species migrates upward dur- 

 ing the night. 



TABLE 55 



Day and Night Distribution of S. serratodentata based on Surface and 

 Horizontal Closing Net Hauls. 



Daylight or 6 a.m. to 6 p.m. 



