334 University of California Publications in Zoology (Vou. 9 
Kofoid net, the latter even appearing in a haul at 550 fathoms; 
these species, however are not as thoroughly characteristic of deep 
water as the others, nor do they possess as much red pigment. 
There is only only black copepod known from this region, Metridia 
atra, which was taken with the Kofoid net at 550 fathoms. 
Hjort (p. 507) evidently inclines to the opinion that red 
animals are protected by the color in deep water, for the red rays 
were not found at 500 meters by means of the Helland-Hansen 
photometer, and red animals at that depth must be as invisible 
as black ones. 
The available data concerning the distribution of the 
Copepoda of this region are not extensive enough to make a dis- 
cussion of this question advisable. It may be pointed out, how- 
ever, that the upper limit for red animals as given by Hjort for 
this latitude (700-800 meters or about 435 fathoms) seems to be 
farther down than our data would lead us to believe. The 
extreme limits within which the largest numbers of individuals 
are taken are 200 and 400 fathoms, but horizontal closing hauls 
below 350 fathoms are greatly needed to determine this point 
more satisfactorily. The general fact of the red forms being 
taken at much higher levels during the night than during the day 
is most evident, as shown also by Hjort (1911, pp. 503 and 504). 
He states, however, (p. 509) that out of 3600 transparent larvae 
and young fishes, 90 per cent were taken between the surface 
and 150 meters. We find that transparent copepods (such as 
Eucalanus) are obtained at practically all depths, and it cer- 
tainly seems that a transparent form would be as invisible at 400 
fathoms as anywhere else. This whole matter is an exceedingly 
important and interesting one and well worth further study; 
at this time such suggestions as have been given above and else- 
where (Esterly, 1911a) are all that are warranted. 
T have not found that our data indicate that there is a relation 
between the locality in which a haul at the surface is made and 
the abundance of any of the species. Likewise, there is nothing 
to be noted as to the seasonal distribution. Possibly this is 
because the greater portion of our collecting was done in June, 
July, and August. 
In conclusion, I do not wish to be understood as having 
