94 THE VOYAGE OF H.M.S. CHALLENGER. 
smooth and nearly even. Pores of both kinds with simple circular mouths, irregularly 
scattered. Gastropores larger, less numerous, with a deeply-seated brush-like style, 
and very thin and delicate tabule placed at irregular intervals. Dactylopores devoid 
of a style. Ampulle, in male stocks, ovoid, entirely immersed beneath the surface 
of the ccenosteum. Pores and ampulle more abundant on one face of the flabellum 
than on the other. Gastrozooids cylindrical, with four club-shaped tentacles, dividing 
at their bases into four main canals. Dactylozooids of various sizes, retracted entirely 
within the pores when at rest. Gonophores, in male stocks ovoid, with a club-shaped 
spadix ; one, two, or three present in each gonangium, attached directly to offsets of 
the ccenosarcal canals. Female stocks unknown. 
2. Pliobothrus, Pourtalés. 
Coenosteum branching, with a tendency to form a flabellum. Surface smooth, marked 
with small linear openings, arranged in rows, which in the recent state contain branches 
of the superficial ccenosarcal meshwork. Inner parts of the ccenosteum very coarsely porous. 
Pores irregularly scattered. Gastropores circular-mouthed, their cavity tubular above, 
but expanding below into a basin-shaped chamber, without a style, often with one 
or two tabula. Dactylopores showing as minute openings at the tips of small tubular 
projections, devoid of styles. Ampulle rounded cavities ; in the female very large, in the 
male smaller; placed deeply, often in the axis of the ccenosteum. Gastrozooids flask- 
shaped, devoid of tentacles,’ communicating with the coenosarcal meshwork by numerous 
offsets arising all around their bases. Dactylozooids entirely retracted when at rest. 
In the female a single gonophore in each gonangium ; in the male, a group of 
gonophores (?) in each ampulla. 
3. Errina, Gray. 
Ccenosteum branching, with a tendency to form an irregular flabellate expansion. Pores 
most abundant at the tips of the branches; irregularly scattered. Dactylopores with 
delicate nariform or scale-like projections, which vary much in form, being sometimes 
drawn out into tubes opening on one side by a slit as the pore mouth, but often 
coalescing, so that two or three projections have a common base and form large scales 
perforated by the pores; devoid of styles ; scales all with a tendency to incline towards 
the tips of the branches. Gastropores with irregularly circular mouths, often seated in 
depressions ; with a deeply-seated style. The mouths of the gastropores frequently 
covered by the dactylopore projections inclined more or less over them. Sometimes 
the margin of the gastropore itself is raised up on one side into a scale inclined over 
the pore mouth, but this is usually fused with neighbouring dactylopore projections. 
Ampulle on both sides of the flabellum, prominent in the female; immersed in the 
1 See note on p. 48, 
