54 BRITISH FOSSIL CORALS. 



Lithodeadron gibbosum, 1 and which belongs also to the lower Chalk formation, but is found at 

 Bochum, in Westphalia, and at Blaton, near Mons, in Belgium. It differs from 8. Sharpeana, 

 by its calices being more closely set ; rather oblong, with a more prominent margin, and 

 twenty-four nearly equal, very thick septa, separated by an equal number of rudimentary 

 ones. The other is the Madrepora Meyeri, found by MM. Koch and Dunker in the 

 Jurassic formation at Elligser-Brinke ; it has deep calices. 2 



The unique specimen here described appears to have been found in the lower chalk 

 near Dover, and was kindly communicated to us by Mr. Daniel Sharpe. 



Family EUPSAMMIDjE (p. li). 



Genus Stephanophyllia (p. liii). 

 Stephanophyllia Bowerbankii. Tab. IX, fig. 4, 4 a, 4 b, 4 c. 



Stephanophyllia Bowerbankii, Milne Edwards and J. Haime, Monogr. des Eupsammides, 



in Annales des Sciences Naturelles, 3 rae serie, Zool. 

 vol. x, p. 94, 1848. 



Corallum simple, resembling, in its general form, a plano-convex lens. Wall 

 discoidal and horizontal. Costa numerous, delicate, nearly equal, closely set by pairs, and 

 formed by a simple series of granulations, which become the most distinct near the outer edge 

 of the mural disc. Twenty-four of these costse begin near the centre of the corallum, and soon 

 after bifurcate ; the forty-eight costse thus produced soon divide again, in the same manner, 

 and near the edge of the disc the number of these radiate ridges amounts to ninety-six. 

 The mural pores are small, not very distinct, and arranged in series in the intercostal 

 furrows. Calice quite circular, and appearing to be regularly convex, excepting towards 

 the centre, where there is a slightly-marked, shallow fossula. Columella almost rudimentary, 

 and formed only by two or three trabiculse, which are often scarcely distinct from the edges 

 of the septa. These last-mentioned organs arise from the upper surface of the mural disc, 

 and are thin, especially outwards, closely set, and covered laterally with large, prominent 

 granulations. They form five complete cycla, and represent six well-characterised and 

 equally-developed systems. The primary and secondary septse are straight, and extend to 

 the columella ; their upper edge is arched, or slightly angular. The tertiary septa are also 

 much developed, and bend towards the secondary ones, to which they become united by 

 their inner edge, near the columella. The septa of the fourth and fifth orders, constituting 

 the fourth cyclum, are united in a similar way to the tertiary septa, at about half way from 

 the margin of the mural disc to the columella, but not exactly at the same point, those of 



1 Petref. Germ., vol. i, tab. xxxvii, fig. 9. 



2 Beitrage zur Kenntniss des Norddeutschen oolithgebildes, p. 55, tab. vi fig. 11, 1837. 



