Messrs. Young on new Carboniferous Polyzoa. 335 
4, the cell-areas are of unequal size and number on the two 
faces. 
In Plate IX. the two faces are shown, and a transverse 
section exhibiting the proportions of the central axis. The 
specimens are in the Hunterian Museum. 
In the Explanation of Sheet 23 (Mem. Geol. Survey Scot- 
land) Mr. R. Etheridge, Jun., refers (p. 102) to “a species of 
Polypora, bearing a considerable resemblance to P. verrucosa, 
M‘Coy. ‘The portions obtained are fragments of a robust 
branching coralline, with a nearly circular section, and a 
generally strong and thick appearance, covered with numerous 
cell-apertures arranged in alternating lines on the celluliferous 
aspect, five or six apertures in each oblique line. ‘The cells 
are very pustulose or wart-like, with prominent raised margins. 
The interspace between each aperture is occupied by waving 
strie, and in some few specimens appears roughened. In 
P. verrucosa, M‘Coy, the apertures are round, in the present 
species they are oval; the margins are equal all round, here 
one is more projecting than the other. It has also a more 
robust and stronger appearance than M‘Coy’s species. ‘The 
reverse presents the peculiar roughened look previously noticed. 
As it has only, hitherto, been found in fragments, the general 
habit and nature of the dissepiments cannot be stated. ‘The 
disposition of the cells and mode of branching are exceedingly 
like those seen in Thamniscus dubius, Schl. (King, Perm. Foss. 
p- 45, pl. v. fig. 9). In the generic description of Polypora, 
M‘Coy (Synopsis Carb. Foss. p. 206) states that the margins 
of the cell-apertures are never raised. As the margins in the 
present form are decidedly raised and prominent, might it 
not be a species of Thamniscus? If it be a new species of 
Polypora, { would propose for it the specific designation of 
P. pustulata.” 
We have received from Dr. Rankin, of Carluke, specimens 
of the fossil in question, so well preserved and showing the 
habit so clearly that we are enabled to give the following 
description. 
Thamniscus ? Rankini, sp. nov. Plate IX. bis. 
Stems free, dichotomous, circular, about >! inch in diameter ; 
branches in one plane. Celluliferous face equal to two thirds 
of circumference. Cells arranged in spirals, the left-handed 
series longer than the right-handed. Cell-apertures circular 
when entire, becoming oval when worn; lower lip prominent ; 
