88 
M. SASAKI. 
IDtite 
Beginning of 
collection 
Duration of 
collection 
Condition of 
sea 
Specific gravity 
of sea water 
Numlicr of 
eggs 
'9' 3 
April 19 
X a. m. 
50 minutes 
calm 
1.0152 
2 
April 20 
VI 1/2 a. m. 
I hour 
calm 
1.0165 
II 
April 22 
VI a. m. 
40 minutes 
calm 
1.0150 
3 
April 29 
I a. m. 
I hour 
calm 
1.00695 
0 
May 2 
X a. m. 
I hour 
calm 
1. 01 1 1 
0 
May 6 
VI a.m. 
I hour 
calm 
1. 0144 
21 
May 7 
IX a. m. 
J I hour 
calm 
1-0154 
12 
The repeated investigations made by Mr. S. Matsuno had verified the fact 
that the eggs float in greatest numbers on the sea surface a little more than 
half a mile off the coast. And the season in which the eggs are collected 
most thickly on the surface agrees with the fishing season along the coast of 
Toyama Bay. The eggs obtained earlj^ in the fishing season show an earlier 
developmental stage, thus confirming the opinion that the littoral migration 
of this animal is simply for the purpose of spawning. 
11. Conclusion. 
Hotani'ika caught in enormous quantities in Toyama Bay have the follow- 
ing habitual characters : 
a. A large percentage of them belong to the female sex; these are suf- 
ficiently matured, carrying spermatophores fixed by the male. 
b. There should be many more males than are caught in spring. 
c. The littoral migration is for spawning. 
After the preceding investigation, I examined many specimens HjLiru- 
ika from Sagami Bay preserved at the Zoological Institute, Science College, 
Imperial University, Tokyo, and found from them many interesting facts which 
seem to verify my preceding opinions. These specimens in the order of 
seasons caught are arranged as follows : 
i) 81 specimens, — all matured males, captured at Shirahama, Awa Province, 
Feb. 9, 1908. The mantle-length being measured from 12 out of the whole 
number varies from 36—45 mm. 
