1912] Esterly: Copepoda of the San Diego Region 283 
be included in this study enables us to arrange the data in 
a much more useful manner than was done previously. Table 
12, which follows, shows how Calanus is distributed at the sur- 
face according to the time of day. 
TABLE 12 
Distribution of Calanus finmarchicus at the surface, by two-hour periods 
through the day. Net A. 
Time of No. of hauls No. of hours No. of animals Frequency 
Day Total Success. Total Success. Total Per hour Haul Time 
a.m. A Cc D E Kg G H 
a 6-8 35 15 27.2 12.3 2491 91 43 41 
2. 8-10 21 9 20.2 11.4 1640 80 43 51 
3: 10-12 14 7 9.8 6.1 103 . 10 50 62 
p.m. 
4. 12-2 14 8 9.0 6.0 92 10 DT 66 
5. 2-4 14 5 Shi 3.5 663 68.5 36 36 
6. 4-6 13 6 9.9 5.0 900 69.2 46 51 
(6 6-8 30 23 19.9 15.4 3643 175.0 74 7 
8. 8-10 8 8 4.4 4.4 4285 973 100 100 
9. 10-12 1 1 2.8 2.8 3825 1375 100 100 
a.m. ES 
10. 12-2 3 3 2.6 2.6 151 58 100 100 
11. 2-4 8 12.0 12.0 1177 97.2 100 100 
12. 4-6 41 25 26.6 13.0 514 19.3 61 53 
Table 13 is a summary of table 12, and is self-explanatory. 
TABLE 13 
Summary of table 12 
Day Night 
1. Total number of hauls ..................-- 111 92 
2. Number of successful hauls............ 50 67 
3. Dotall mumber of Howrs:2--22-----.-.22- 85.6 69.5 
4. Number of successful hours............ 43.3 47.7 
5. Total number of animals.................. 5889, 14574. 
6. Average per hour 218.0 
he seta) Sire qWeNC yee cere eee eee 75 
So uilimle “frequen ciyse-cee cn oee eee ees 75, 
This table shows in a very striking manner the greater 
abundance and frequency at night (lines 5-8), though there 
are not so many night as day hauls, nor so many hours spent 
