288 University of California Publications in Zoology \Vou.9 
It is fair to conclude from table 15 that the vertical nets 
indicate that there is a movement away from the upper water 
during the day, and a movement away from deeper water at 
night. It is true that the differences between day and night 
hauls as shown in table 15 are not great but taken in connection 
with the results from surface and horizontal closing collections, 
they are suggestive. Emphasis should be laid on the fact that 
there are no vertical hauls above 50 fathoms and at night before 
2 a.m., and that it is between 8 and 12 p.m. that the animals are 
obtained in greatest abundance with the surface net; and fur- 
thermore that during the same time and above 50 fathoms they 
were taken in largest numbers by the Kofoid net. It is to be 
expected that with these omissions the results of collecting with 
the vertical nets will not be so clear as with the others, and 
that the differences in abundance between day and night will 
not be so great. At any rate, judging from the data available 
at this time, there is evidence from all the nets that Calanus 
performs diurnal migrations. This conclusion should not be 
cast aside because the three types of nets do not agree in all 
respects, for a larger number of hauls more uniformly distri- 
buted as to time will probably smooth out the irregularities. 
Distribution with regard to temperature.—tIn considering the 
relation between temperature and the occurrence of Calanus, 
IT used 130 surface hauls made in June, July, August and Sep- 
tember. These were chosen in order to do away with possible 
seasonal changes, for the temperatures in the months named run 
about the same. Temperatures for closing net hauls are not 
known. 
The results reached are very irregular. As an indication 
of this table 16 has been constructed. It contains the ten hauls 
of the 130 that took the largest number of specimens; these 
are all night hauls in either June or July. The hauls were 
made between the hours in the column at the left. 
