490 SEITARO GOTO 
Locality. — Between ]\Iisaki and Jogashima. 3 hiro^'^ deep, covering 
worm-tubes resembling gastropod shells, inhabited by a hermit crab in 
place of the dead worm. 
Date.— April, 1889. Collected b> Mr. Shishido. 
The hydrorhiza is very strongly built but very thin, hence it is easy 
to prepare sections of it. The original wwm tube was probably very 
delicate and hardly leaves any of its traces; the w^hole lamella consisting 
of the creeping hydrorhiza of the Podocoryne. Perisarc not elevated in 
the form of a bowl at the base of the hydranths. The chitinous spines 
are hollow and filled with a coenosarc consisting of the two layers and 
ending blindly. Som.e of the spines have incomplete or exceedingly thin 
apices; these are probably growing ones. 
The upper surface of the hydrorhizal lamella is covered by a naked 
coenosarc, which has been described as consisting only of the ectoderm, 
but which, according to my own observation, appears to contain also the 
endoderm; this point requires reexamination. 
The hydranths are very small, the larger ones being 1.5 mm. high 
and the smaller ones bearing medusoids not being over 0.5 mm.; the 
spines are 0.5-0.7 mm. high. 
Of the medusoid gonophores there are generally two on a hydranth, 
the lower one being the larger; the full grown medusoid comparatively 
large, with a diameter of over 0.2 mm. 
This is a very interesting species and probably new. The genus Podo- 
corj^ne usually produces free medusae and Hydractinia gonophores 
which are never detached. The present species is intermediate on this 
point, the reproductive organs being medusoid and never detached. 
Hence it may be somewhat doubtful to which of these two genera to 
refer it, but the presence of the four radial canals in the reproductive 
organs (fig. 7), and of tentacles on the hj^dranths bearing them, or blasto- 
styles, leaves no doubt that it belongs to the genus Podocoryne. 
According to Allman, there is no doubt that the Hjdra aculeata of 
Wagner is a Podocoryne. In this species the medusa does not complete 
its development, being never free, although there are four radial canals 
and four tentacles on the edge of the umbrella; hence it is evident that 
there are several stages in the development of the medusa within the 
genus Podocoryne. The description of P. aculeata agrees fairly well with 
my specimens; possibh thej' are the same species. R. Wagner is stated 
to have obtained it in 1833 on the coast of the Adriatic Sea. but it has 
not been obtained since. 
^' A "hiro " is an arm-span, equal to about 1.6 m. 
