DEVELOPMENT OF GUCUMARIA ECHINATA 187 
branches, and a white thread-like spermatic fluid flowed out from 
each. Being heavier than sea-water, the spermatic fluid sank 
down as a milky white cloud on to the bottom of the vessel. 
In females the shedding of eggs seemed to be accompanied by 
no waving of tentacles, but eggs were thrown out intermittently 
on the hinder aspect. The egg is much heavier than sea-water 
and very soon sinks to the bottom. 
According to Kowalewsky (1%, p. 1), who put about 
fifty freshly-caught individuals of C. kirehsbergii into a 
large vessel through which fresh sea-water flowed, the emission 
of sperm by males occurred within two hours. The spermatic 
fluid formed a white thread streaming out of a pore situated 
between tentacles, and was then stirred up by the waving move- 
ment of the latter. The emission of sperm lasted for about an 
hour, and in the next hour a female lying near began to shed 
eggs. He seems to have believed that the ege was fertilized 
inside the mother’s body and was expelled through the pore 
in the body-wall, and that in a viviparous form, Phyllo- 
phorus urna, this pore serves as a birth-pore. Selenka 
(45, p. 166) observed no waving of tentacles in the male 
C. planci while emitting sperm, and according to him the 
females which began to shed eggs as soon as the males emitted 
sperm moved their tentacles very actively. Des Arts 
(2, 1910, p. 3) put a great number of C. frondosa into an 
aquarium, and the first night saw the laying of eggs which 
were soon fertilized. According to Newth (86, p. 633) the 
spawning of C. normani takes place in the night, and generally 
near midnight. On one occasion males and females lying 
together in the same tank began to spawn within a few minutes 
of one another. Isolated individuals of both sexes are said 
to have spawned too, but he was never successful in fertilizing 
the egg so shed by adding sperm suspension, and I cannot 
help doubting whether he was careful to ascertain that the 
females really spawned without being stimulated by spermatic 
fluid. 
Of other pedate holothurians records are given by Selenka 
(45, p. 157) on Holothuria tubulosa, and by Edwards 
(12, p. 212) on H. floridana. Among some dozens of big 
