A monograph of the British fossil corals - kreidefossilien.de

54 BRITISH FOSSIL CORALS.
Lithodendron gihhosum^ 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. Sharpecma,
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.^
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 EUPSAMMIDJ3 (p.
li).
Genus Stephanophyli-ia (p. liii).
Stephanophtllia Bowerbankii. Tab. IX, fig. 4, 4 a, 4 h, 4 c.
Stephanophyllia Bowerbankii, Milne Edwards and J. Haime, Monogr. des Eupsaramides,
in Annales des Sciences Naturelles, 3"" serie, Zool.
vol. X, p. 94, 1848.
Corallum simple, resembling, in its general form, a plano-convex lens. Wall
discoidal and horizontal.
Costa nixmerous, 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 costfe 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 sejda.
These last-mentioned organs arise from the upper sm-face of the mural disc,
and are thin, especially outwards, closely set, and covered laterally with large, prominent
granulations. They form five complete cycla, and repi'esent six well-characterised and
equally-developed systems. The primary and secondary septae 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.
- Beitrage zur Kenntniss des Norddeutsclien oolithgebildes, p. 55, tab. vi fig. 1 1, 1837.