282 University of California Publications in Zoology |Vou.9 
In considering the distribution and movements of the species 
named in table 11, the data for the four styles of nets have 
been studied separately, and arranged so. In all other cases 
except hauls with vertical closing nets the number of animals 
has been reckoned on the basis of a haul one hour in length; 
such numbers are called hourly averages or number per hour 
and are obtained by dividing the total number of animals by 
the total number of hours. The term “‘haul frequeney’’ means 
the percentage of successful hauls—the ratio between hauls in 
which the species was taken and the total number of hauls. 
ay 
“Time frequency’’ is the percentage of hours of successful haul- 
ing or the ratio between the time occupied by hauls in which 
the species was taken and the total time spent in hauling. Fre- 
quency has no reference to abundance of animals; the frequency 
would be the same for a given number of hauls whether one 
animal or a hundred were taken in each haul. 
The whole day has been divided into twelve periods of two 
hours each and the time from 6 a.m. to 6 p.m. is referred to as 
““day,’’ while that from 6 p.m. to 6 am. is called ‘‘night.’’ 
These designations are more or less arbitrary since they have 
no necessary relation to sunrise or sunset. 
Disrripution of Calanus finmarchicus. 
According to the statements of Sars (1904, p. 11) this form 
should be referred to as C. helgolandicus. It seems to me, 
however, that there can be no doubt that the species is C. fin- 
marchicus, and Wolfenden (1904, p. 126) is of the opinion that 
the factors on which Sars bases the distinction are too inconstant 
to be admissible. 
This species was found in a larger proportion of all hauls 
than any other, being taken in 412 out of 680: the haul fre- 
quency is 61. I have discussed the vertical distribution of 
Calanus on a basis of 23 surface hauls and 73 hauls with the 
Kofoid closing net (Esterly, 1911b) and while there are 114 of 
the latter hauls available now it is unnecessary to repeat the 
discussion, since the additional number of hauls does not affect 
the conclusions arrived at before. This is also true of the surface 
hauls in a general way, but the larger number of hauls that can 
