General History of the Marine Polyzoa. 163 
on which each individual shoot is supported may certainly be 
regarded as the representative of such a structure as the stem 
of Kinetoskias. ‘The rods originate from the side of a zocecium, 
and rise to a height (including the terminal stems above) of 
about half an inch; they are much thicker than the ordinary 
radical fibres. There are sometimes one or two twists or 
imperfect annulations at the base, and (as I have mentioned) 
immediately below the cup they are distinctly and very 
prettily ringed. As many as seven (or perhaps more) may 
rise from one of the basal triplets. The portion of the celli- 
ferous stem immediately above the cup, from which the dicho- 
tomous branches originate, differs somewhat from the rest. 
The cells composing it are furnished with a much larger 
number of spines than is usual (as many as six), and they 
almost form a continuous whorl round the stem (Pl. VIII. 
fig. 46*). ‘The cup at the summit of the rod must be regarded 
as made up of partially aborted cells placed closely side by 
side, the spines of which constitute a perfect ring. 
The zocecia which carry avicularia are destitute of spines, 
the avicularian swelling occupying the position in which they 
are usually developed. ‘The spines are a very characteristic 
and conspicuous feature of the species. They are of very great 
length, tubular and transparent, rising in twos or threes im- 
mediately below the aperture from a tubular base (to which 
they are jointed) ; they continue almost straight or slightly 
curved for a short distance, and then bend abruptly upwards, 
overarching the zocecia and completely enveloping and em- 
bowering the stems. ‘The zoarium is composed of delicate, 
glossy, translucent material. 
I have not had the opportunity of making an examination 
of the genus Kinetoskias ; but in Rhabdozoum we seem to have 
a somewhat parallel form belonging to the Eucratean group. 
Family Membraniporide. 
Group a (fLusrrip2Z). 
Zoarium corneous and flexible, foliaceous, erect (in the 
adult state). Zowc’a with raised margins; front wall mem- 
branaceous or membrano-calcareous. 
Friusrra, Linneus. 
Flustra reticulum, nu. sp. (Pl. VII. fig. 4.) 
Zoarium branched dichotomously, of a dark colour when 
* This is a rough camera lucida sketch; but it gives a fair idea’ of 
the general appearance of this'region of the zoarium. 
Ile 
