194 REPORT—1883. 
Family V. Potyporip2. 
Zoarium forming large or small fenestrated expansions. Zowcia con- 
tiguous; with three rows and upwards of cell-openings in a row, on one 
side only. Branches united by dissepiments or by anastomosis. 
Genus Polypora, M‘Coy. Type P. dendroides, M‘Coy. 
»,  Lhyllopora, King. » L. Ehrenbergii, Geinitz. 
These two genera differ in the anastomosis of the branches, but in 
the arrangement of the cells in the branch there is a striking similarity 
between them. The Fenestella intermedia, Shrubsole, of the Silurian 
rocks, appears to be a kind of connecting link between the two groups, 
Fenestellide and Polyporide. The F. intermedia occurs in the Niagara 
rocks at Lockport, as well as in our own Wenlock series. The branches 
are occupied alternately by two and by three rows of cells, so that it is 
rather a difficult matter to decide to which family group it should be 
referred. 
Tn a recent paper on Phyllopora (‘ Quart. Journ. Geo. Soc.’ vol. xxxviii. 
p. 347) Mr. Shrubsole says that from the Devonian rocks (Palaeozoic 
Foss.) Phillips figures the Phyllopora with circular fenestr as Retepora 
prisca ; that with lozenge-shaped fenestra as Fenestella anthritica, and that 
with square fenestr as Gorgonia ripisteria. As might be expected, there is 
considerable confusion of species in Phillips’s delineation of the Devonian 
Polyzoa; two or more varieties are included under one head (op. cit. 
p- 384). This is to be regretted, but, as Mr. Shrubsole says, it is almost 
impossible to make a revision of Devonian Polyzoa on account of the 
difficulty of obtaining material for the purpose. We are indebted to 
Professor Nicholson for much valuable information in his descriptions of 
Polyzoa in his paper on ‘New Devonian Fossils’ in the ‘ Geological 
Magazine,’ 1874. The various species of Polyzoa described by Nicholson 
are from the ‘ Devonian formation of Canada West.’ 
Potypora, M‘Coy. 
Zoarium a delicate or robust, reticulated calcareous expansion ; 
branches round, connected by thin dissepiments. Zowcia contiguous, 
with from three to five rows of cell-openings in a branch, on one side 
only ; marginal cells occasionally projecting. 
Carboniferous . Polypora dendroides, M‘Coy. 
5 tuberculata, Prout. 
55 laxa, Phill. 
Puytiopora, King (‘ Permian Fossils,’ p. 40). 
Zoarium consisting of an infundibuliform or foliaceous expansion. 
Zoccia on one side only, and occupying the whole surface of the branch ; 
cells contiguous. Branches united by anastomosis, and not by dissepi- 
ments. 
Lower Silurian . Phyllopora 
Upper Silurian . 55 sp. 
Devonian . F Fe prisca, Phillips. 
Carboniferous . 3 
Permian. ‘ 95 Ehrenbergii, Geinitz. 
t i multipora, Shrubsole. 
