186 HIROSHI OHSHIMA 
layer of connective tissue and a layer of loose irregularly arranged 
muscular fibres. 
6. SPAWNING. 
The late Professor Mitsukuri observed on one occasion 
that the spawning had begun at 5 p.m., and in another that 
it had continued from 7.30 to 10.30 p.m. My experience is as 
follows : 
At 5 p.m. on July 25, 1916, several specimens were brought 
to the Station, and soon after that I found two individuals 
emitting spermatic fluid. Half an hour afterwards, at 5.80, 
another individual began to lay eggs. In the morning of August 1 
of the same year some few specimens were got and brought into 
the Station at 1.15 p.m. Soon afterwards two individuals 
were found emitting sperm, but in this case no laying of eggs 
was seen to follow. At about 2.30 p.m. of the same day plenty 
of large specimens were brought in. Here the emission of 
sperm by a male was found to begin at 5.25 p.m., and a female 
which was lying about 5 cm. distant from the former began to 
shed eggs at 5.40, which continued till about 6.30 p.m. In 
the specimens of the same lot kept in another jar the emission 
of sperm by one began at 4.50 p.m. followed by several others, 
but no shedding of eggs took place here. 
These specimens were all quite big, and later examination 
showed that all of them were sexually ripe and contained sperma- 
tozoa or eggs in abundance. In the individuals which missed 
the chance of shedding genital elements, I noticed that it never 
took place the next evening or at any later time. Even exposing 
the animals in a warm sunny place with very little sea-water, 
or putting them in the dark, could not cause them to spawn. 
According to Mitsukuri (ante, p. 174) unclean water makes 
the animal lay eggs. 
The male, while emitting spermatic fluid, stretched out its 
tentacles half-way and kept them very quiet. The spermatic 
duct could be seen through the body-wall as a white streak 
which appeared to perform a peristaltic movement. In conse- 
quence of the subdivision of the spermatic duct at the genital 
papilla, that white streak could be seen divided into five or six 
