248 BRITISH FOSSIL CORALS. 



This species is of a more regular cliscoidal form than any others of the same genus. 

 P.porpila} which is also very flat, differs from it by the septa being alternately large and 

 small. 



3. Pal^ocyclus Fletcheri. Tab. LVII, figs. 3, 3a, 2>b, 3c, 3d, 3e, 3/. 



Pal.;eocyclus Fletcheri, Milne Edwards and Jules Haime, Pal. Foss. des Terr. Palaeoz. 



(Arch, du Mus., vol. v), p. 205, 1851.— Ann. des Sc. Nat., 

 3d ser., vol. xv, p. Ill, 1851. 



Corattum very short, but of a subturbinate form, with a short, strongly curved 

 peduncle, a thick epitheca, and some well developed accretion wrinkles. Calico circular, 

 or almost so, with a somewhat deep cavity, and a lamellated edge. 30 or 3S principal 

 septa, alternating with an equal number of small ones ; somewhat thick, closely set, not 

 tall, and scarcely exsert; their edge slightly convex, and provided with raihc..' strong 

 denticulations, which, closely set exteriorly, become more distant towards the centre, and 

 scarcely ever form a double row on the same septum. Diameter of the calice about 8 

 lines ; height of the corallum about 4 lines. 



In the young specimens the peduncle is more developed proportionally. In an aged 

 individual, that measured almost 12 lines in diameter, and that does not appear to differ 

 specifically from the former, the marginal denticulations of the principal septa are almost 

 obsolete exteriorly. 



Dudley. Collections of Mr. T. W. Fletcher, and of M. Bouchard-Chantereaux 

 (Boulogne). 



By its general form, this species is intermediate between P. porpita" and P. rugosus / 

 its septa are also more numerous and more strongly denticulated than in either of these 

 fossils. 



4. PaLjEOcyclus rugosus. Tab. LVII, figs. 4, 4a, 4b, 4c, 4d. 



Pal^ocyclus rugosus, Milne Edwards and Jules Haime, Pol. Foss. des Terr. Palseoz. (Arch, 

 du Mus., vol. v), p. 206, 1851. — Ann. des Sciences Nat., 3d ser., 

 vol. xv, p. Ill, 1851. 



Corallum cylindro-turbinate, sometimes rather elongate ; its basis subpedunculated, much 

 bent, and compressed ; epitheca thick, and presenting strongly developed accretion wrinkles, 

 which are very oblique near the basis. Calice circular, with a large, and somewhat deep 

 cavity. Principal septa (26 or 28) alternating with an equal number of small ones; 

 somewhat thick, with their edges regularly denticulated, and slightly arched interiorly. The 



1 See tab. lvii, fig. 1. 2 See tab. lvii, fig. 1. 3 See tab. lvii, fig. 4. 



