470 
SEITARO GOTO 
tioned a species of Hydractinia living in symbiosis with it.' 
Since Stimpson's paper is not accessible to me I have no basis 
on which to form my own opinion, but if, as Stechow says, Stimp- 
son devoted only two lines to the characterization of his Hydrac- 
tinia sodalis, it is very doubtful whether it was precise enough to 
enable one to decide which of the two species mentioned at the 
beginning of this paper was before him. Since, however, it is 
not desirable to introduce unnecessary confusions into zoological 
nomenclature, which threatens to become formidable, I prefer 
to accept Stechow's identification. The other species is, in my 
opinion, new, and I propose the name of Hydractinia spiralis 
for it. These two species are the subjects of this paper, and it is 
but fitting that I should dedicate it to the memory of the lamented 
Dr. Brooks, since it was from him that I received m}^ first ad- 
vanced instruction in hydroid morphology. 
1. HYDRACTINIA SODALIS STIMPSON 
The skeletons of this species are rather common and sold in 
a dry state at Enoshima and other places, where they are known 
as ''Igaguri-gai," or ''chestnut burr shell.'' I have been told that 
when Prof. E. S. Morse was here he was interested in these ''shells," 
and was aware that there was always a gastropod shell in the apex. 
Aside from Stimpson, whose reference to this species has been 
above mentioned, Inaba is the only author who to my knowledge 
has described the animal. Owing, however, to the difficult condi- 
tions under which he had to work, he regarded it doubtfully as 
a species of Podocoryne. His description is as follows:^ 
36. Podocoryne sp.? (Figs. 103, 104, 105.) 
Trophosome. — The chitin of the hydrorhiza is very strong and 
bears at places chitinous spines with branches. Hydranths large, 
growing out in numbers from a hydrorhizal substratum; there are 
two forms of hydranths, one large, the larger ones 5 mm. high and 1 
mm. across, with about 30 filiform tentacles arranged in a single row 
= Stimpson: '58, p. 225. ^ inaba: '92, p. 96. 
