TRANSACTIONS OF WAGNER 
ON THE LIFE HISTORY OF AN ECONOMIC CUTTLEFISH OF JAPAN 
The mature females ordinarily met with are not so fully matured, with their 
ovary less than half full of mature eggs and with the nidamental glands less 
than 120 mm. in length. The table gives, among various data, the sexual 
Ti 
TEN 
ASTM rer ee > 
ee 
is ; 
deere = - 
rey EVEN AY 
OE 
| 
Zz 
Z 
= 
2 
2 
2 
z 
17% 
\Z 
\ 
. 
IBiG3Ae 
Mantle of a fully mature female 
Nibanzurumé, dissected along the 
midventral longitudinal line, X 14. 
n, Nidamental gland; no, 
external orifice of nidamental 
gland; od, oviduct; og, oviducal 
gland; oo, genital opening; ov, 
ovary. 
maturity of the female specimens which I have 
obtained from Oki. 
From the table on p. 8, based upon ana- 
tomical examinations, we conclude that in Oki 
the principal spawning period confines itself 
to about September and October, even 
though the spawning continues all the year 
round, while the principal pairing period is 
extended from summer to winter; in short, 
the principal spawning period is much shorter 
than the principal pairing period. From the 
occurrence of the animal parallel data can also 
be collected. In nearly all warmer seas plank- 
ton feeding juveniles of the cuttlefish as 
caught with various kinds of fishing nets are 
most abundant synchronously with spring. 
In addition to this, the individuals caught at a 
certain season of the year are, on the whole, of 
approximately the same size. The gregarious 
occurrence of the same- or nearly same-aged 
individuals indicates a certain season in which 
they have been hatched out, and which repre- 
sents, accordingly, a principal spawning per- 
iod. On the other hand, in the collections 
taken all over the year there are found numer- 
ous young specimens measuring up only to 30 
mm., proving that the spawning is taking 
place all the year round. As before men- 
tioned, in the Bay of Toyama nearly all stages of growth were collected at a 
time and in Oki grown individuals have been caught at nearly all seasons. 
In other words, the spawning season continues throughout the year, just as 
we have pointed out from the anatomical side. 
