76 
M. SASAKI. 
The total amount of the annual catch reaches generally about looo tons, 
though it shows some fluctuation, and in 1913 it reached a little above 900 
tons, the statistics here being taken directly from the notes of fishermen 
engaged in that fishery. Hoiaru-ika caught there are mostly mature 
females ; young ones have not been found. 
For facilities and useful advice given me in the present work, it is 
my pleasant duty herewith to return my cordial thanks to Prof. Dr. T. 
Fujita. 
I. HABITS OBSERVED FROM THE ZOOLOGICAL 
POINT OF VIEW. 
1. Sexual Dimorphisms. 
The characteristics of the female Hoiani-ika have been already made 
public by S. S. ]?erry (Proc. Acad. Nat. Sei. Philadelphia, 191 2, p. 425), 
and the specimens examined by me practically agree with his description 
except in details, which do not seem sufficiently important to be stated 
here. 
The principal sexual differences based on the study of 20 formalin 
specimens of each sex obtained in the period from April 25 to May 7 
are as follows : 
Female. — The mantle-length is 54-67 mm. This is about the minimum 
and maximum limits of the mantle-length of the fully mature female, for 
I have never met with any beyond these extremities. 
Two-sevenths of the mantle at the anterior is cylindrical. From 
thence it tapers gradually and is pointed at the posterior end. The fin 
is large and very broad, the breadth being distinctly greater than the 
length, which is slightly less than 2/3 of the mantle-length (PI. I, fig. i). 
The pen is of the Loligo-ty^e and wide, the breadth being a little 
less than 1/5 of the length (PI. II, fig. i). 
Male. — The body is a little smaller than that of the female, the mantle- 
