228 BRITISH FOSSIL CORALS. 



AsTREA HELIANTHOIDES, Lonsdale, Geol. Trans., 2d. ser., vol. v, p. 697, 1840. 

 DiscoPHYLLUM HELIANTHOIDES, D' OrUgny, Prod, de Paleont., vol. i, p. 106, 1850. 

 Cyathophyllum HELIANTHOIDES, Milne Edwards and Jules Haime, Pol. Foss. des Terr. 



Palseoz., p. 375, pi. viii, fig. 5, 1851. 

 Strephodes HELIANTHOIDES, M'Coy, Brit. Palseoz. Foss., p. 73, 1851, 



Corallum simple or composite. 



When simple this species is subturbinate, short, broad, with the edge of the calice 

 reverted, so as to form an obtuse prominent ridge around the central fossula. Sixty or 

 eighty equally-developed septa, slightly thickened towards the exterior by the granulations 

 and striae that arise from their lateral surfaces ; almost all of these extend to the centre of 

 the calice, where they become slightly curved, and present, in the well-preserved 

 specimens, small but well-characterised paliform lobes, which, by their agglomeration, 

 form a sort of crown near the centre of the calicular fossula. The edge of the calice is 

 circular and slightly lamellate. The height of the corallum is usually about two inches, 

 and in that case the diameter of the calice is about double, or somewhat more, and 

 that of the paliform circles about four lines. 



When composite this corallum assumes an astreiform appearance, and the coralhtes, 

 which are united together side by side, are circumscribed by polygonal lines, usually not very 

 prominent. The calices are in general smaller than in the simple specimens, very unequal 

 in size, and not provided with as many septa. In a variety of this species, the calicular 

 swelling is large and prominent. Vertical sections show that the central part of the 

 visceral chambers is occupied by slightly-developed tabulae, and the outer parts filled with 

 numerous and somewhat regular vesicles. 



Found at Plymouth, Teignmouth Beach, and Mudstone Beach; in France at Vire 

 (Sarthe) ; in Germany, in the Eifel, Rokeskill, Blankenheim, Steinfeld, Luxembourg, 

 Reinfeld, Sigmaringen ; in America, at Harrisville, Ohio, and in the Isle of Mackinaw. 



British specimens are in the collections of Mr. J, S. Bowerbank, Dr. Battersby, 

 and Mr. Pengelly. 



The species of cyathophyllum that most approximates C. helianthoides is C. Begium^ 

 from the mountain limestone ; but in the latter the simple coralhtes are more regularly 

 turbinate, and the calice is not everted so as to assume the form of a mushroom ; the 

 septa are also more numerous and slender. 



9. Cyathophyllum hexagonum. Tab. L, figs. 4, 4a. 



Madrepora truncata? Esper, (Pflanz.) Petref., tab. iv ; (not Linne). 

 Cyathophyllum hexagonum, Gold/uss, Petref. Germ., vol. i, p. 61, tab. xx, fig. 1, 1826. 

 Favastrea hexagona, De Blainville, Diet. So. Nat., vol. Ix, p. 340, 1830. — Man., p. 375. 

 AsTREA HEXAGONA, Steininger, Mem. Soc. Geol. de France, vol. i, p. 345, 1831. 



' Tab. xxxii, fiss. 1 — 4. 



