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, 1 from Bala, Merionethshire. 



Petraia subduplicata, M'Coy. 2 



Petraia serialis, M'Coy. 3 



Turbinolopsis rugosa, Phillips, 4 from Snowdon. 



3. Genus Omphyma (p. lxviii). 

 1. Omphyma turbinata. Tab. LXIX, figs. 1, la. 



Fungites gothlandicus, &c, Magnus Bromel, Act. Liter. Suec, vol. ii, p. 461, 1728. 



— major, &c, Ibid., p. 462. 



Madrepora simplex, turbinata, *■" , Foufft, Amaen. Acad., vol. i, p. 87, tab. iv, figs. 1, 2 



(Cat. excl.), 1749. 



— turbinata, Linne", Fauna Suec, p. 536, 1761. 



— — Limit, Syst. Nat., ed. 12, p. 1272, 1767. 



— — Esper, Pflanz. (Petref.), tab. ii, figs. 1, 2 (Cat. excl.). 

 Turbinated madreporite, Parkinson, Org. Kemains, vol. ii, pi. iv, fig. 2, 1808. 

 Turbinolia turbinata (pars), Lamarck, Hist, des Anim. sans Vert., vol. ii, p. 231, 1816 ; 



2d edit., p. 360. 



— cyathoides, Lamarck, Ibid., p. 231. 



Madreporites turbinatus (pars), Wahlenberg, Nov. Act. Soc. Upsal., vol. viii, p. 96, 1821. 

 Turbinolia cyathoides and turbinata, Lamouroux, Exp. Metb., p. 51, 1821. 



— — Deslong champs, Encyc. (Zooph.), p. 750, 1824. 



— — Defrance, Diet. Sc. Nat., vol. lvi, p. 91, 1828. 

 Caryophyllia turbinata (pars), Al. Bronyniart, Tabl. des Terrains, p. 431, 1829. 

 Caninia lata, M'Coy, Ann. and Mag. of Nat. Hist., 2d ser., vol. vi, p. 277, 1850. 



— — M'Coy, Brit. Palaeoz. Foss., p. 28, pi. i c, fig. 13, and perhaps also fig. 12, 



1851. 

 Omphyma turbinata, Milne Edwards and Jules Haime (Introd., p. lxviii, 1850), Pol. 

 Foss. des Terr. Palaeoz. (Arch, du Mus., vol. v), p. 400, 1851. 



Corattum 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. Calice subcircular; its edge slightly lamellated. 

 Calicinal cavity large and deep ; the uppermost tabula presenting an extensive smooth 

 surface in the middle, and four well-characterised septal fossulae, 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 tabulae are horizontal, broad, and well developed. The lateral parts of 



Brit. Palaeoz. Foss., p. 40. 2 Ibid., p. 40, pi. i b, fig. 6. 3 Ibid., p. 41, pi. i b, fig. 25. 



1 Palseoz. Foss. p. 7, pi. ii, fig. 7 c. 



