40 PERMIAN FOSSILS. 
resemblance to the genus Ptylopora of M‘Coy. These modifications are represented 
in Plate IV, fig. 5. The bifurcation of the stems appears to be caused by the 
addition of one cr more longitudinal rows of cellules. A stem goes on increasing 
in width for a while, through the interposition and gradual development of a new row 
of cellules; after which it divides: both divisions then increase in length, each one 
afterwards dividing in the manner described. The cellules have a raised margin 
surrounding their aperture; and their cast shows them to be curved, overlying each 
other, and slightly contracted at their upper part (vide diagram under figure 6, Plate IV). 
The so-called gemmuliferous vesicles alternate with the adjoining cellule-apertures : 
they often leave their impression in the form of a pit intervening between the rows 
of impressed cellule-apertures, when the celluliferous surface of the fossil is in the 
state of an impression, as exhibited in figure 4, Plate IV ; occasionally, however, a 
specimen occurs with the celluliferous surface itself exhibited, as in figure 5, Plate IV, 
in which case the (?) gemmuliferous vesicles are seen to be tubercular, and open at the 
summit. Sometimes specimens are found furnished with simple root-like processes 
on the under side of the fronds (vide Plate IV, figs, 7 and 8), similar to those already 
noticed when describing enestella retiformis. 
Synocladia virgulacea is rather a common species in some localities, as at Humbleton 
Quarry, Ryhope Field-house Farm, Dalton-le-Dale, and Hylton North-Farm. It is 
less common at Tunstall Hill, and very rare at Whitley. In all these localities it is 
found in the Shelly Magnesian Limestone. I found a small specimen in Breccia at 
Tynemouth Chiff. It does not appear to have been noticed either in Germany or 
Russia. 
Genus Phyllopora, King, 1849. 
GorGonta (EHRENBERGI), Geinitz. 
FENESTELLA (PERMIANA = EHRENBERGI), King. 
Diagnosis —* A Fenestellidia consisting of infundibuliform, folded, perforated 
fronds or foliaceous expansions. Ce//ules on the whole of the outer or under surface 
of the fronds; and planted more or less approximating to a position at right angles to 
the plane of the capillary-tubular basal plate. Cel/ule-apertures with plain margins, 
and parallel to the surface of the fronds.”* 
Type, Gorgonia Ehrenbergi, Geinitz. 
In order that the present group be properly appreciated, it has been deemed 
necessary to make a few observations on the genus /efepora, and another one lately 
published in the ‘Annals and Magazine of Natural History’ under the name of 
Elasmopora. Lamarck founded his fefepora on three or more species of very dissimilar 
structure, some of which have already been made typical of other genera; the type, 
1 Annals of Natural History, 2d series, vol. 11, p. 389. 
