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LOWER SILURIAN ROCKS NEAR WELSHPOOL, WALES. 109
sent some fossils to Professor Lapworth for identification. Amon^^st
them were some Polyzoa. These Professor Lapworth asked Mr.
Morgan to send to me, and their study has enabled me to throw a
little light on essentially characteristic features of at least one Lower
Silurian species of PhyUopora. This is clearly not the P. Hlsinrjeri
of authors, and I shall be compelled, much against my wish, to
characterize it as new.
Fig. 1. — Portions 0/ PhyUopora tumida, sp. n.
(Enlarged 6 diameters.)
A. Poriferous surface.
B. Interior of non-celluliferous face.
1. Phyllopora tumida, sp. n. Fig. 1.
Zoarium an open net-work of undulating branches ; base and
general dimensions of zoarium unknown, branches anastomosing,
apparently thick, occasionally tumid, and varying in breadth from
one tenth to one twelfth of an inch. Fenestrules oval or irregular,
sometimes less, but occasionally rather longer than the breadth of
the branches. Zocecia tubular, short or stunted, cell-mouths circular,
prominent, with a rather thick peristome, from four to five arranged
diagonally in the branch. Reverse, on account of the peculiarity
of its preservation, indistinct.
Horizon and Locality. Caradoc beds ; "Wern-j-seadog, Llanfyllin.
Cabinet, J. B. Morgan, Esq., Welshpool; 2 specimens.
I have been fairly successful in drawing a portion of two branches,
on which the cell-characters are pretty distinct. The specimen
from which the drawing is made is rather more than half an inch
square ; it contains about twenty-three perfect and imperfect
fenestrules, and nearly the whole of the branches are more or less
covered with cell-apertures (fig. 1, a). In places where the cells are
worn the tubular prolongations are seen, and, judging from the
peculiarities of the form, I should not imagine that the branches are