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 



Q. J. G. S. iS^o. 162. K 



