174 HIROSHI OHSHIMA 
‘June 18, 1899. Mitsukuri arrived at the Station to-day, 
being informed of the fact that in these days Messrs. Aoki 
and Tsuchida had observed the spawning of Cucumaria 
echinata.’ 
‘ June 20. Ifsome freshly caught specimens of C.echinata 
are kept in a glass vessel, it is almost certain that they will spawn 
in the evening.’ 
‘July 21. C. echinata spawned !’ 
‘July 29. C. echinata caught in the morning began to 
spawn at 5 p.m.’ 
‘ August 11, 1902. Kuma Aoki dredged several scores of 
C. echinata at the mouth of the inlet of Koajiro. They 
began to spawn at 7.30 p.m. and went on till about 10.80 p.m. ; 
a very large number of eggs were spawned. Mitsukuri 
engages in the study of them.’ 
In his memoir on pedate holothurians (81, 1912, p. 242) the 
late professor has recorded with reference to the above facts 
as follows: ‘In the breeding season (the summer) the ripe 
individuals throw out reproductive elements. The males shoot 
forth the spermatic fluid, after which the females begin to 
shed eggs, which easily undergo development under observation.’ 
So far as the results of his study are concerned, unfortunately 
no report was made, except his two short addresses delivered 
at the monthly meetings of the Tokyo Zoological Society. The 
contents of those addresses can now be recovered only from 
unpublished notes made by a member who attended the meetings. 
The first address was given on December 16, 1899, under the 
title ‘General Account of the Embryology of Holothurians °. 
The notes may be translated as follows : 
‘To obtain eggs of C. echinata it 1s necessary to tease 
the animal and not to change the water. Animals captured 
in the morning will lay eggs in the evening. They are in an 
extended posture while laying eggs; the genital products are 
emitted from the interradially situated genital pore in the form 
of a streak. The amount of the products of each emission is 
very remarkable. No peculiar points are noticeable in the 
segmentation of the eggs. In the five-tentacled stage a pre-oral 
