298 University of California Publications in Zoology (Vou. 9 
TABLE 24 
Summary of table 23 
Specimens Total Successful 
per fathom hauls hauls Frequency 
Day Night Day Night Day Night Day Night 
Between 0 and 50 fathoms 40.0 48.0 122 115 53 «83 43 72 
Between 50 and 250 fathoms 5.8 8 41 27 33 «20 80 74 
We may gather from table 23 that the daylight plurimum 
is near 200 fathoms (lines 12 and 13) as was shown by the 
Kofoid net as well (Esterly 1911b). Though there is a pluri- 
mum at 30-25 fathoms nearly as large as that at 200 fathoms, 
the frequeney for the former depth is 65, while for the latter 
it is 100. This probably means that the larger proportion of 
the animals is at 200 fathoms or thereabouts. 
In table 24 it is plain that these animals are more abundant 
and more frequent above 50 fathoms by night than by day. 
The number per fathom at night below 50 fathoms is only 
about one-seventh of that during the day, and the night fre- 
queney is smaller. Since the vertical and horizontal nets both 
show that the hourly averages are smaller in deep water by 
day than by night, and since the surface net takes more at 
night, we are justified in assuming that the organisms move 
upward at night. There is no such clean-cut evidence of daily 
oscillation as was obtained for Calanus and, while more hauling 
might show such a condition for Hucalanus, there is no more 
reason at present for attributing its manner of distribution to 
the methods of collecting than to the organisms themselves. 
Distribution with regard to temperature.—As in the case of 
Calanus, we are limited to surface hauls for evidence as to 
the effect of temperature on the distribution of Hucalanus. The 
species was obtained in 31 hauls out of the 130 for which the 
temperature is known. Table 25 is intended to show the distri- 
bution as regards temperature. 
