1914] Esterly: Schizopoda of the San Diego Region 131 



less successful than those during the rest of the year. There are some 

 curious discrepancies, however, between the parts of the table. In 

 part I, Nyctiphanes appears only in December hauls, but in fairly 

 large numbers, while with the vertical nets (part II) only eleven 

 animals were captured. Euphausia was most abundant in December 

 in the horizontal nets and in March in the vertical nets. 



Table 5 agrees with table 4 in regard to the seasonal occurrence 

 of Nyctiphanes, but Euphausia was most abundant in June and July 

 in the surface collections (table 4) instead of in the spring or fall, as 

 in the hauls with closing nets (table 5). 



As far as our data go at the present time, the Schizopoda are 

 shown to be more abundant at all levels during the colder portion of 

 the year (November through April), as is indicated in the following 

 summary of tables 4 and 5. The season of colder water is referred 

 to as "winter", for convenience, and is contrasted with the "summer", 

 or warmer months. 



A total of 191 hauls in summer at the surface took 207 specimens 



A total of 83 hauls in winter at the surface took 567 specimens 



A total of 104 hauls in summer with the Kofoid net took 18 specimens 

 A total of 67 hauls in winter with the Kofoid net took 1066 specimens 

 A total of 320 hauls in summer with the Nansen net took 5 specimens 

 A total of 323 hauls in winter with the Nansen net took 1150 specimens 



Since there is, apparently, such a sharply defined seasonal occur- 

 rence, we may consider the distribution of Euphausia and Nyctiphanes 

 (as the more important species) at the surface with regard to temper- 

 ature, since that factor varies noticeably with the season. As a matter 

 of convenience, the distribution of the surface hauls, in water of 

 different temperatures, is given by months in table 6. 



TABLE 6 



Distribution of Surface Hauls by Months According to Different Temperatures 



Temperature 



Feb. 



March 



April 



June 



July 



Aug. 



Sept. 



Oct. 



Nov. 



Dec. 



Total 



14° and less 



5 







2 



























1 



8 



14?1-15° 





3 



21 



5 



























7 



36 



15?1-16° 





2 



5 



1 











1 











1 



4 



14 



16?1-17° 









1 



4 



25 



4 



2 



1 







3 



5 



45 



17?1-18° 

















27 



1 















2 







30 



18?1-19° 

















11 



9 







3 



2 



1 







26 



19?l-20° 

















10 



3 



9 



1 



13 











36 



20?1 and 



more 



















9 



23 



1 



2 











35 



Total 





10 



27 



12 



73 



26 



35 



6 



17 



7 



17 



230 



