CORALS FROM THE SILURIAN FORMATION. 287 
it in this Monograph (Tab. LXVI, figs. 6, 6a), in order to give an exact idea of the form 
of such casts. 
Petraia elongata, M‘Coy,’ from Bala, Merionethshire. 
Petraia subduplicata, M‘Coy.” 
Petraia serialis, M‘Coy.* 
Turbinolopsis rugosa, Phillips,* from Snowdon. 
3. Genus OMPHYMA (p. Ixvin). 
1. Ompnyma turBINaTA. Tab. LXIX, figs. 1, la. 
Funerres Goratanpticus, &e., Magnus Bromel, Act. Liter. Suec., vol. ii, p. 461, 1728. 
— masor, &c., Ibid., p. 462. 
MabREPORA SIMPLEX, TURBINATA, &c., Fougt, Ameen. Acad., vol. i, p. 87, tab. iv, figs. 1, 2 
(Cet. ewxcl.), 1749. 
—_ TURBINATA, Linné, Fauna Suec., p. 536, 1761. 
— — Linné, Syst. Nat., ed. 12, p. 1272, 1767. 
— — Esper, Pflanz. (Petref.), tab. ii, figs. 1, 2 (Cet. evel). 
TURBINATED MADREPORITE, Parkinson, Org. Remains, vol. ii, pl. iv, fig. 2, 1808. 
TURBINOLIA TURBINATA (pars), Lamarck, Hist. des Anim. sans Vert., vol. ii, p. 231, 1816; 
2d edit., p. 360. 
—- cyaTHorpEs, Lamarck, Ibid., p. 231. 
MADREPORITES TURBINATUS (pars), Wahlenberg, Nov. Act. Soc. Upsal., vol. viii, p. 96, 1821. 
TURBINOLIA CYATHOIDES and TURBINATA, Lamouroux, Exp. Meth., p. 51, 1821. 
— —_ Deslongchamps, Encye. (Zooph.), p. 750, 1824. 
—_ — Defrance, Dict. Se. Nat., vol. lvi, p. 91, 1828. 
CARYOPHYLLIA TURBINATA (pars), AZ. Brongniart, Tabl. des Terrains, p. 431, 1829. 
Cantnta Lata, M*Coy, Ann. and Mag. of Nat. Hist., 2d ser., vol. vi, p. 277, 1850. 
— — MCoy, Brit. Paleoz. Foss., p. 28, pl. ic, fig. 13, and perhaps also fig. 12, 
1851. 
Ompnuyma TuRBINATA, Milne Edwards and Jules Haime (Introd., p. Ixvii, 1850), Pol. 
Foss. des Terr. Paleeoz. (Arch. du Mus., vol. v), p. 400, 1851. 
Corallum simple, turbinate, straight, short, often twice as broad as high, subpedicillated, 
and bearing radiciform appendices in its lower half only. Epitheca thin, and presenting 
in general only slight accretion wrinkles. Cadice subcircular ; its edge slightly lamellated. 
Calicinal cavity large and deep; the uppermost ¢adu/a presenting an extensive smooth 
surface in the middle, and four well-characterised septal fossula, two of which are larger 
than the others. Septa (100 or 120) thin, not tall, and resembling simple folds, somewhat 
unequal in dimensions alternately, straight or slightly flexuous towards the centre of the 
calice. The lower ¢adule are horizontal, broad, and well developed. The lateral parts of 
Brit. Paleeoz. Foss., p. 40. 2 Tbid., p. 40, pl. 18, fig. 6. 3 Tbid., p. 41, pl. i 8, fig. 25. 
4 Palzeoz. Foss. p. 7, pl. ii, fig. 7 ©. 
