the Submarine-Cable Fauna. 173 
the hydrothecz in regular verticils, and the branchlets con- 
tracted in a very remarkable manner at their junction with 
the branches. 
Genus Scapus, Norman, n. g. 
Zoophyte in the form of a spongious mass rolled in cylin- 
drical form round the stems of branching Hydrozoa (Acrypto- 
larva), and consisting of a series of somewhat closely packed 
subquadrate hydrothece, closed in above, except at the centre, 
where the hydrotheca projected in the form of a short, simple, 
cylindrical horny tube. 
Scapus tubulifer, Norman,n. sp. Pl. XII. fig. 1, a, & fig. 3. 
Zoophyte growing in little roll-like masses round the 
larger stems of Acryptolaria exserta (Busk), almost every 
specimen of which was the bearer of this parasitic species, 
though none of the other zoophytes procured at the same time 
and place showed a vestige of it. The roll-like mass has 
a soft spongious character, the external crust being harder. 
It consists of a large number of hydrothece, which, on a 
section being made, prove to be subquadrate in form, and 
packed closely together without any interspaces; the hydro- 
theca is closed in above except at the centre, where it is raised 
in the form of a short tubular orifice, rising from the mass of 
the hydrozoary ; this tube is often slightly, but never much 
bent. 
At first sight this species bears a strong resemblance to 
Coppinia arcta, from which, however, we at once know it by 
the more elongated and delicate character of the rolls and 
by the much shorter tubuli. In organic structure, however, 
the two species are very distinct from each other. In Cop- 
pinia the basal mass consists of chitinous cells rendered 
polygonal by mutual pressure, these cells are the gonothece ; 
while the slender-tubed hydrothece pass through the mass to 
the base of the hydrozoary, and are of equal diameter from 
the base to their free extremities (see a paper on the structure 
of Coppinia by Allman, Brit. Assoc. Report, 1868, p. 87, 
published subsequently to Hincks’s work). In Scapus the 
basal mass consists of the hydrothecze, which are bottle-shaped, 
expanded below and forming the mass, and contracted above 
into narrow projecting tubes. 
Sertularella polyzonias (Linn.). 
Gayt (Lamx.). 
Diphasia pinaster (Ellis & Sol.). 
alata (Hincks). 
