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G. K. VINE ON THE WEDLOCK POLYZOA.
67
Localities. Buildwas beds, No. 38 only

Coalbrookdale beds, very
rare fragments

Tickwood beds, No. 25 and No. 42.
Fig. 14. — Ptilodictya interporosa, Vine.
A portion of the branch of one specimen, showing the central and lateral
arrangement of cells with the intercellular spaces filled with smaller open-
ings: X 12.
20. Ptilodictya intekpokosa, sp. n. (Tig. 14.)
Zoarium consisting of a thin, narrow, branching frond of unknown
extension. Zocecia arranged in two orders

the median row, or
rows, may or may not be perpendicular to the base, and may con-
sist of from one to four rows

for this character is very variable

the
lateral rows are oblique, extending to the margin of the zoarium,
which is rather sharp-edged, but without any marginal striae

cells
oval, slightly compressed in the middle, rather larger towards the
margin. The whole of the cells are surrounded by minute openings
("interstitial tubules"*) which, becoming filled in, in the older
growth of the colony present the appearance of a minutely granular
peristome to the cell. About four cells, with their "interstitial
tubules," occupy the space of a line in either a longitudinal or oblique
direction, and about six transversely. The compressed character of
the median rows in one specimen alters this measurement slightly

but the clearly defined character of the cells of this species is
unmistakable.
Locality. Tickwood beds, No. 42.
This beautiful species is founded upon ten fragments, the longest
of which is not more than a quarter of an inch in length. The
characters, however, are so distinct and so unlike those of any other
Ptilodictya that I know of, that I cannot do otherwise than describe
it as new. At first sight the specimens may be mistaken for a Fis-
tulipora, M c Coy

but although hundreds of fragments of Fistulipora
are found in the same beds, only the ten specimens of this, as above-
named, have been found. The orifices of the cells of P. interporosa
are distinctly oval

in Fistulipora they are circular

and in the
zoarium of this latter species there are non- cellular spaces which
are filled in with interstitial tubuli of a most marked character. In
Of Nicholson.