140 BRITISH FOSSIL CORALS. 
at first sight considered them as belonging to two distinct species, but on closer exami- 
nation that no longer appeared to be the case. 
We are also inclined to think that the Astrea helianthoides of Prof. M‘Coy! is a worn 
specimen of the same species, and that the Agaricia elegans’ of that author may be a 
young individual of this 7amnastrea. 
The above-described fossil is found in the Inferior Oolite at Dundry, and in France 
near Bayeux. Specimens are in the collections of the Geological Society, Mr. Bowerbank, 
Mr. Walton, and Mr. Pratt. 
Thamnastrea Defranciana is remarkable for its general form, which resembles that of 
certain sponges, and for the tenuity and close approximation of its septa. It is very nearly 
allied to a fossil of the cretaceous formations, Tamnastrea conferta, but in the latter the 
columella is more developed, and the septa more flexuous. Some other species, 7. ¢enu- 
wssima’ and T. velamentosa, for example, also bear great resemblance to 7. Defranciana, 
but differ from it by having much smaller calices, thicker septa, and a more developed 
columella. 
2. THamMNnastRea Teravuemi. Tab. XXX, figs. 2, 2a, 26. 
Corallum i general thin, circular, and adherent at the centre of its basis, but sometimes 
appearing to have been quite free; its common basal plate covered with a thick epitheca, 
presenting concentric folds or wrinkles ; its upper surface flat or slightly convex. Calices 
quite superficial and rather closely set. Colwmel/a small. Senta from twelve to sixteen in 
number, unequal alternately, irregularly confluent, often geniculate and grossly granulated 
laterally. Breadth of the calices two lines. In one specimen the corallum was made up 
of superposed layers arranged obliquely. 
This species was found by Dr. Wright in the Inferior Oolite near Cheltenham, and 
fo) 
by M. Terquem at St. Quentin, near Metz. 
7. Terquemi differs from most species of the same genus, by the irregular and rude 
appearance of the septa; which are thick, but not as much so as in 7. Lennisi® and 7. 
Belgica.’ The same character distinguishes it also from 7. Mettensis,* which, in other 
respects, it resembles very much. 
1 Ann. and Mag. of Nat. Hist., s. 2, vol. ii, p. 401. 
2 Op. cit., p. 418. 
3 Synastrea conferta, Milne Edwards and J. Haime, Ann. des Sc. Nat., s. 3, vol. xii, p. 190. 
* Synastrea tenuissima, Milne Edwards and J. Haime, loc. cit., p. 191. 
Astrea velamentosa, Goldfuss, Petref. Germ., vol. i, tab. xxiii, fig. 4. 
© Astrea Lennisii, Roemer, Verst. des Norddeut. Kreid., tab. xvi, fig. xxv. 
~ 
Milne Edwards and J. Haime, Polyp. Foss. des Terr. Paleeoz., &c., p. 100. 
5 See tab. xxx, fig. 3. 
