TRANSACTIONS OF WAGNER 
ON THE LIFE HISTORY OF AN ECONOMIC CUTTLEFISH OF JAPAN 
than in the northern part of Japan. In Hokkaidé the fishing is carried on usually 
from July to November, while in Oki its season continues all the year round 
except March and April, when the sea water there is coldest. The cuttlefish is 
usually most abundant everywhere in summer, so that sometimes it is called 
“Natsu-ika”’ (summer squid). The cuttlefish of the northern waters differs 
from that of the southern waters in the modes of the development and matur- 
ation of the reproductive organs as well as in certain characters of the habit, 
which will be considered later (pp. 13,14). At all events these facts all tend to 
disprove the view of a long migration of the schools from Kiushiu to Hokkaid6. 
The fishing is carried on daily from evening to morning, the best catch 
being obtained at somewhile after sunset and before sunrise. Even in day- 
time, by the use of suitable methods, one may catch the animal, though small 
in amount. Repeated experiences of angling show that in the daytime the 
cuttlefish are most abundant in the water strata from 50 fathoms to 100 
fathoms, although such strata of the thickest population seem to differ in some 
degree in different seasons and localities. Numerous hydrographic observa- 
tions made while fishing show us that the water temperature suited for the 
living of the cuttlefish is from 10° C. to17° C., but that the animal of the north- 
ern seas is adapted to colder water than the southern form. From the facts 
above mentioned we may guess the daily migration of the cuttlefish to be as 
follows: They swim in daytime usually in the strata from 50 to 100 fathoms 
which are the part of the sea hardly penetrated by the daylight, as has been 
proved in oceanography. As the sun sets, they come up and are crowded 
together in the sea strata of about 20 fathoms or even near the surface, as if 
seeking a region of weak daylight. Towards midnight they again scatter 
themselves or sink, but are gathered once more near the surface before the sun- 
rise. During these daily vertical migrations, however, the animal seems not 
much affected by the change of temperature, since this often varies greatly in 
the different water strata which it crosses. 
Although there seems to be no special leader among a school, they are apt 
to move after a member which is excited; it is from this peculiar habit that one 
of the members angled up is followed by the remainder, which are thus easily 
brought up toward the surface; and when one is frightened by an enemy or 
by any other cause, all will at once disappear. 
