CORALS FROM THE SILURIAN FORMATION, 253 
same genus. In most other respects 7. Grayi much resembles H. Murchison’ and H. 
inordinata,? but may be distinguished from both by the circular exsert margin of the 
calices. 
The fossil figured in M. Murchison’s justly-celebrated work under the name of 
BLUMENBACHIUM GLoBosuM Lonsdale,’ appears to be a mould of a coral belonging to the 
above-described species. It was found at Wenlock. 
5. Henionires rorpinata. Tab. LVI, figs. 7, 7a. 
Portres INoRDINATA, Lonsdale, in Murchison, Silur. Syst., p. 687, pl. xvi dis, fig. 12, 1839, 
LonspaLia INorDINATA, D’ Orbigny, Prodr. de Paléont., vol. i, p. 25, 1850. 
PaLmopora suBTILIS? M‘Coy, Brit. Paleeoz. Foss., p. 17, 1851. 
HELIOLITES INORDINATA, Milne Edwards and Jules Haime, Pol. Foss. des Terr. Paleoz. 
(Arch. du Mus., vol. v), p. 217, 1851. 
Corallum arborescent, very ramous ; its branches slender, subcylindrical, and about one 
or one and a half line in diameter.  Ca/ices not prominent, circular, or somewhat elongated 
in the longitudinal direction of the branches, and set at various distances from each other 
in different parts of the corallum. Sepéa 12 in number, nearly similar in size, rather thick, 
and well developed. Cells of the ccenenchyma polygonal and somewhat irregular. 
Diameter of the calices about half a line. 
Found in the lower Silurian beds at Robeston Walthen, Pembrokeshire. According 
to Professor M‘Coy it exists also in the upper Silurian deposits at Ferriter’s Cove, 
Doonquin, and Dingle, in Kerry. The fossil which Professor M‘Coy describes under the 
name of Paleopora subtilis,* and which (from the description given by that author) we are 
inclined to consider as not differing specifically from /7. cwordinata, appears to be common 
in the fine Caradoc sandstone of Mulock, Dalquorhan, Ayrshire. Specimens are in the 
Collection of the Geological Society. 
The above-described species differs from the other Heliolites by its dendroidal form, 
and by the development of its septa. 
2. Genus PLasmopora, (p. lix.) 
1, Puasmopora prratirormis. Tab. LIX, figs. 1, la, 14, le. 
PoritEs PETALIFoRMIs, Lonsdale, in Murchison, Silur. Syst., p. 687, pl. xvi, fig. 4, 1839. 
ASTREOPORA PETALTEFORMIS, D’ Orbigny, Prodr. de Paléont., vol. 1, p. 50, 1850. 
PaLmopora PETALIFORMIS, M‘Coy, Brit. Paleeoz. Foss., p. 17, 1851. 
PLASMOPORA PETALIFORMIS, Milne Edwards and Jules Haime (Introd., p. lix, 1850), 
. Polyp. Foss. des Terr. Paleeoz., p. 221, 1851. 
1 See tab. lvii, fig. 6. 2 See tab. vii, fig. 7. 3 Silurian System, tab. xv, fig. 26, 
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