428 Mr. J. Young on the Identity of Ceramopora 
until it becomes a true Monticulipora—the organism in ques- 
tion being the Berenicea megastoma, M‘Coy, Diastopora, 
Morris’s Catalogue, but which has been more correctly reterred 
to Ceramopora by G. R. Vine, in his paper ‘On the Family 
Diastoporide,” Quart. Journ. of the Geol. Soc., Aug. 1880, 
. 359. 
‘ I shall not now enter upon any exhaustive description of 
this organism in its several stages, but briefly state that it is 
found in its first or earliest stage in small, circular, incrusting 
patches, 3 lines in diameter, or what M‘Coy terms “ spot- 
like crusts,” attached to shells, stems of Crinoids, Polyzoa, 
Corals, &c., the cells being depressed or oblique, and radia- 
ting outwards from a bare central spot-or macula. 
In its next stage it is found in similar incrusting patches, 
varying in size from a half inch to two or more inches in ex- . 
tent. In this stage the cells are still much reclined, and have 
their mouths of a trilobed form when quite perfect, but roundly 
triangular or pyriform when the outer surface is worn. The 
more perfect trilobed form of the cell-mouths is due to the 
occurrence of two short spines that project, one on each side, 
on the raised lower lip of the cell—a character that has like- 
wise been noticed in some of the Silurian Ceramopore. In 
some specimens in this stage of growth the cell-mouths are 
seen to be closed by a thin calcareous cover, which I now 
consider to be the commencement of tabulee in the cells. In 
the spaces between the cells there are also numerous small 
polygonal cells that are arranged in from one to three rows. 
I first called attention to these new characters in C. megastoma, 
M‘Coy, in the Trans. of the Geol. Soc. Glasg. vol. vi. p. 2138, 
1879; but at that time I had not seen Dr. Lindstrém’s paper, 
and had no idea that the organism afterwards developed into 
a Monticulipora. 
The next stage is where we find the organism in thicker in- 
crusting patches, in which the larger cells are seen to become 
more erect, while their mouths become nearly circular, the 
openings in some specimens being quite round, with a slightly 
raised rim to the cell; but the roundly triangular form of the 
cell-mouths of the earlier stage can always be traced in such 
specimens when sections of the organism are cut near the base. 
In this stage, which Dr. Lindstrém calls the third, we often 
find the small polygonal cells or tubes that occupy the space 
between the larger tubes closed by a thin, dense, calcareous 
outer layer, which leaves only the larger cell-openings visible. 
This he terms the Thecostegites-stage ; but when this is the 
case the smaller tubes can always be exposed by grinding a 
little way below the surface, so as to remove this layer. It 
