MADREPORARIA OF THE BOULONNAIS. VAL 
say, 1t would be possessed of true synapticule and a non-porous 
structure of the tissue of the corallum. 
The coral here described, while preserving the outward form and 
appearance of a Latumewandra, possesses a structure which approxi- 
mates it to Thamnastrea arachnoides, from which it differs in having 
much thinner and much more numerous septa, and more fully deve- 
loped walls. 
I have already, in a former paper on Coral-Rag Madreporaria, 
suggested that the well-known Thamnastreea arachnoides possesses 
some peculiarities which render its place in the genus Thamnastrea * 
very doubtful. The present allied species, with its well-developed 
walls, occasions still more doubt as to its affinities with that 
imperfectly defined genus, and points to the necessity for its revision. 
It occurs at Hourecq, from which place a single specimen has been 
forwarded. 
THAMNASTR@A ? concinNA, Goldf. sp. 
Asirea concinna, Goldf., Petref. Germ. t. i. p. 64, pl. 22. fig. 1a. 
Thamnastrea concinna, M.-Edw. & Haime, Pol. Foss. Terr. Paléoz. 
eta. 
From information supplied by M. Rigaux, I learn that this 
common species is as well known in the Coral Rag of Boulogne as in 
that deposit in this country. Several specimens kindly forwarded at 
different times for my use came from the middle Kimmeridge of 
Belledale, the Coral Rag of Hourecq, the Coralline Oolite of the 
Mont des Boucards, and the Lower Calcareous Grit of Houllefort. 
It has been placed in the genus Thamnastrea by Milaschewitsch, 
but with an expression of doubt. In that doubt I fully participate. 
THAMNASTR#A FOLIACEA, Quenst. sp. 
Agaricia foliacea, Quenst. Handb. d. Petref. 1 Aufl. p. 651. 
When compared with examples of Thamnastrea foliacea from the 
Corallian of Nattheim, several specimens which have been collected 
from the Coral Rag of Boucard and Hourecq by M. Rigaux are seen 
to agree so closely as to render their identification easy and certain. 
THAMNASTR&A GIBBOSA, Becker, Palesontographica, vol. xxi. p. 170, 
plexes. 3. 
A specimen from the Coral Rag of Houllefort differs chiefly from 
the figure given by Becker of this species in having the short septa 
sometimes passing into the longer or primary ones. The latter are 
from eight to ten in number, and the columella, as shown in Becker’s 
figure, is styliform. 
THAMNASTRZA, Sp. 
A much worn coral, specifically undeterminable, but obviously 
nearly related to Thamnastrea concinna, has been met with by 
M. Rigaux at Chatillon in the Lower Portland Oolite or in the beds 
* Quart. Journ. Geol. Soc. vol, xxxix. p. 558. 
