Prof. Allman on the Hydroida. 61 
Campanulina repens, Allman, n. sp. 
Trophosome—HUy drocaulus springing from a creeping stolon- 
like hydrorhiza, and consisting of numerous short simple stems, 
each terminated by a polypite, and, along with these, other more 
developed stems with alternate branches; hydrothecz conical, 
with the margin continued by a membrane which is cut into 
deep acute segments, forming an operculum which closes over 
the orifice of the hydrotheca when the polypite is withdrawn or 
absent ; the hydrocaulus is distinctly annulated, but the hydro- 
rhizais smooth. Polypites very extensile, with about sixteen ten- 
tacula, rendered nodulose in extension by irregular clusters of 
thread-cells ; the tentacles during extension are held with the 
alternate ones elevated and depressed, and are united at their 
base by a very shallow web. 
Gonosome.—Gonangia large, borne upon the creeping stolon, 
and occasionally also upon the hydrocaulus, about three times 
the length and breadth of the hydrothecz, in the form of an in- 
verted cone slightly gibbous at one side near the proximal end, 
and supported on the summit of a very short annulated pedun- 
cle. Gonophores phanerocodonic ; meduse at the time of libera- 
tion with four very extensive marginal tentacles, which are 
nodulated by clusters of thread-cells. 
C. repens was found investing the surface of Sertularian Hy- 
droids dredged from about 5 fathoms in the Firth of Forth. It 
differs from C. acuminata, Alder, in the hydrotheca being 
crowned by long, acute, converging segments, which on the re- 
treat of the polypite form a true operculum, while the hydro- 
theca in C. acuminata is merely continued by a delicate collap- 
sile and undivided membrane—as well as in the much slighter 
development of the scarcely apparent web which unites the 
bases of the tentacles, and in the fact that the medusa at the 
time of liberation has four well-developed marginal tentacles, 
while the medusa of C. acuminata has only two. Some of these 
characters may possibly be regarded as pointing rather to a 
generic than to a merely specific difference. (See my Synopsis of 
the Campanularian Hydroids, ‘Annals, May 1864, p. 376.) 
In my Synopsis of the Tubularian Hydroids (p. 359), I pro- 
posed the establishment of a new genus, under the name of 
Heteractis, for the Corymorpha annulicornis of Sars. I had un- 
fortunately overlooked at the time the fact that this name had 
been already employed by the botanist for a genus of composite 
plants—an inadvertence to which one of my pupils, Mr. W. R. 
M‘Nab, has since called my attention. 1 would accord- 
ingly now propose that the new zoological genus, instead of 
