1912] Esterly: Copepoda of the San Diego Region 319 
Table 48, which follows, deals with the vertical closing hauls. 
It will be seen that, as in the preceding table, the day plurimum 
is between 200 and 250 fathoms (line 4) and that this region and 
the level below (line 5) are deserted at night. The animals are 
more abundant above 100 fathoms by night, but the results are 
not particularly clear. 
TABLE 48 
Distribution of Scolecithriz persecans as shown by hauls with the 
vertical closing nets, day and night hauls compared 
A B Cc D E 
Total Successful Total Animals per Haul 
Depth hauls hauls animals 100-f. haul frequency 
Day Night Day Night Day Night Day Night Day Night 
aif 40-0 106 100 il! 0 1 0 2 0 0.9 0 
2. 100-40 39 34 0 5 0 5 0 8 0 14 
3 200-100 12 7 9 5 184 37 184 37 75 71 
4, 250-200 6 al 5 0 203 0 406 0 81 0 
5 300-250 4 1 3 0 74 0 148 0 75 0 
Undeuchaeta bispinosa.—This species was taken at the surface 
only at night, when there were five successful hauls containing 
25 animals; 21 of these were taken between 8 and 10 p.m., and 
two between 10 and 12. The temperatures for these hauls range 
from 1829 to 20°2 and the salinities from 33.539 to 33.762. This 
is the only species which oceurs at the surface consistently at 
any temperature (high in this case), there being a range of 123. 
In other cases the range is as much as six degrees. The hauls 
that contained Undeuchaeta are so few that its occurrence with 
reference to temperature is only suggested, but the available data 
are certainly exceptional merely in indicating conclusions as to 
the effect of that factor in determining the distribution of the 
species. 
The distribution of this species as shown by the horizontal 
closing nets is set forth in table 49 which follows. The day 
plurimum is between 200 and 250 fathoms (line 4) ; this region is 
deserted during the night but.the animals were taken between 
4 and 75 fathoms only at night. These facts are evidences of 
an upward movement at night. 
