MADREPORARIA OF THE BOULONNAIS. 707 
ward form and in structural details, so closely with Cryptocenia 
obeliscus as to leave no doubt of its identity withit. It was placed, 
though not without doubt, by MM. Milne-Edwards and Haime 
in the genus Stylina, in their monograph of Paleozoic Corals*, but 
afterwards, in their general work on Corals}, removed to the list of 
doubtful species. M. de Fromentel wholly ignores it. 
CRYPTOCG@NIA PLANA, D. sp. 
The corallum consists of a peduncle surmounted by a swollen and 
globular head, which has a diameter fully three times that of the 
peduncle. 
The calices are large, circular, few in number, prominent, and 
the spaces between them are centrally depressed. The intercali- 
cular costs are very feebly developed, and are only observable near 
the margins of the calices, where they correspond in their relative 
size with the septa. The calices are deep, and their margins are 
thin. There are six principal septa, which also are thin, and pass 
nearly to the centre of the calice. Six others, forming the second 
cycle, are much less prominent, and are about two thirds the length 
of the primary ones. The remaining twelve have still less promi- 
nence, thickness, and length, and constitute the third cycle. 
Gemmation takes place midway between the calices. 
The height of the corallum is 1 inch 6 lines, of which the peduncle 
is one third. The diameter of the head is 1 inch 3 lines; of the 
calices 2 lines; and of the intervals between them 2 lines. 
One specimen only, as I learn from M. Rigaux, has been met with - 
in the Cornbrash of Le Wast. 
Cryprocanta RIGAUXI, n. sp. 
With the Oryptocenia obeliscus, and from the Great Oolite of 
Hydrequent, was received a small specimen of a Cryptocoenia, which, 
having the “ octomeral” type of M. de Fromentel, is quite distinct 
from the C. lucrensis, to which species it was probably referred by 
MM. Milne-Edwards and Haimet. 
The corallum is small and globular, and attached by a small 
space. ‘The calices are about the size of those of C. tuberosa, but 
are rather nearer together. The principal septa, eight in number, 
are stout, pass nearly to the centre of the calice, and unite deep 
in it, but do not there form a spurious columella. In some of the 
calices there are eight other septa, which are merely rudimentary ; 
they constitute, where present, the second cycle. The intercalicular 
cost are stout, prominent, and cristiform, and so much crowded 
as to completely conceal the upper margin of the wall, as in Con- 
vexastrea. They decrease in size rapidly as they recede from the 
calice over the intercalicular space, in the middle of which they 
meet, but do not blend with those of other calices. 
The present species seems to bear some resemblance to the one 
* Pal. Foss. des Terr. Paléoz. p. 60. 
Tt Hist. Nat. Cor. vol. ii. p. 247. 
{ Hist. Nat. Corall. vol. 1. p. 272. 
