CORALS FROM THE GAULT. 3) 
2. Genus CycLocyaTuus (p. XIV). 
Cycnocyatuus Firtoni. Tab. XI, fig. 3, 3a, 36. 
Corallum simple, discoidal, short ; mural disc horizontal, or slightly concave, and pre- 
senting in its centre a small, irregular cicatrix, indicative of its primitive adherence. 
Lpitheca very thin, presenting some slight concentric striae, and not preventing the radiate 
costee from being visible. These are straight, and not very prominent; but those of the 
first and second order are well marked. The edge of the mural disc is thin, and slightly 
prominent. ‘The upper or calicular surface of the corallum is rather convex externally, 
and concave towards the centre. The fossula is shallow, but large, and well marked. 
Columella fasciculate, well developed, and terminated by a broad, papillose surface. Septa 
forming four complete cycla. The six fundamental septal systems distinct, but the septa 
of the second order not differing much from those of the first order. All the septa well 
developed, straight, rather thick exteriorly, arched above, and granulated laterally ; their 
outer edge somewhat crenulated, granulose, slightly concave near the mural disc, and pro- 
jecting a little towards the upper part. Pa/i well developed, very distinct from the septa, 
and corresponding to those of the third cyclum. Height of the corallum, tio or three lines ; 
diameter, in general not more than five or six lines. 
This fossil is the only known species of the genus Cyclocyathus ; its form renders it 
very remarkable. It has been found in the Gault at Cambridge, Drayton, West Malling, 
and Folkstone, but appears to be most abundant in the last-mentioned locality. The 
specimens here described belong to the collections of the Geological Society, of Mr. 
Bowerbank, and of Mr. D. Sharpe. 
3. Genus TROCHOCYATHUS (p. xiv). 
1. Trocnocyataus conutus. Tab. XI, fig. 5, 5a. 
CaRYOPHYLLIA conuLts, (?) Phillips, Must. of the Geol. of Yorkshire, tab. 1, fig. 1, 1829. 
(A rough figure without any description.) 
— — Michelin, Mém. de la Soc. Géol. de France, vol. iii, p. 98, 1838. 
TURBINOLIA CONULUS, Michelin, Icon. Zooph., p. i, pl. i, fig. 12, 1840. 
TrocnocyaTuus conuLus, Milne Edwards and J. Haime, Monogr. des Turbin., Ann. des 
Se. Nat., 3™° série, vol. ix, p. 306, 1548. 
Corallum simple, turbinate, rather elongate, straight or shghtly bent, and pedicellated. 
Wail presenting in general some slight traces of an incomplete epitheca. Costfz simple, 
distinct from the basis, closely set, delicately granulated, not very prominent, and alternately 
