CORALS FROM THE SILURIAN FORMATION. 293 
8. Genus SvROMBODES (p. Ixx). 
1. Srrompoprs typus. Tab. LXXI. figs. 1, la, 10. 
ARACHNOPHYLLUM TyPUs, M‘Coy, Ann. and Mag. of Nat. Hist., 2d ser., vol. vi, p. 278, 1850. 
— — M Coy, Brit. Paleoz. Foss., p. 38, pl. iB, fig. 27, 1851. 
Srrompopes Lapecuit, Milne Edwards and Jules Haime, Pol. Foss. des Terr. Paleeoz. 
(Arch. du Mus., vol. v), p. 427, 1851. 
Corallum composite, massive, subturbinate ; its upper surface slightly convex ; its basal 
common plate covered with a very thin epitheca, and presenting very prominent and 
irregular accretion ridges. The terminal surface of the corallites irregularly polygonal, and 
separated from each other by strong ridges that are more prominent at their angles than 
elsewhere. Near the centre of these polygonal spaces a slight circular elevation, corres- 
ponding to the upper edge of the imer wall, and circumscribing the true calice. Septal radii 
not distinct from the cost, and thus extending to the outer edge of the corallite. The total 
number of the septo-costal radii amounts to about 100, but one third of them only extend 
to the calicinal fossula, where they become curved and somewhat prominent ; most of them 
appear to bear small paliform lobules. ‘The marginal or costal radii are still slenderer than the 
preceding ones, and adhere to them at their inner edge. Veryslender, closely set, unequally dis- 
tinct dissepiments unite all these radii, so as to constitute delicate very regular quadrangular 
reticulations. Vertical and horizontal sections show that the structure of the corallum is 
essentially vesicular. In a section corresponding to the direction of the axis of the corallites, 
the different layers of that vesicular tissue being of different degrees of density, constitute 
undulated parallel horizontal lines, the direction of which correspond to that of the surface 
of the corallum. <A horizontal section shows that the inner or true walls are circular 
and well constituted, and that the reticulations become larger and more regular towards 
the circumference of the corallites. In many parts no remains of the costz septal radii are 
distinct, and the space comprised between the inner wall and the lateral surface of the 
corallites is completely cellular. Large diagonal of the corallites at the upper surface of 
the compound mass about 8 lines; diameter of the true calice about 3 lines. 
Wenlock Edge. Aymestry, Herefordshire (M‘Coy). 
Specimens are in the Collections of the Paris Museum, Bristol Museum, of the Museum 
of Practical Geology, and M. de Verneuil. 
2. StromBoves Murcuisoni. Tab. LXX, figs. 1, la, 14, le, 1d. 
AcervuLarta Baurica (pars), Lonsdale, in Murchison, Sil. Syst., p. 689, pl. xvi, figs. 84, 
8e, 8d, 8e (Cet. excl.), 1839. (Not Schweigger.) 
Actinocyatuus Batricus, D’ Orbigny, Prodr. de Paléont, vol. i, p. 48, 1850. 
Srrompopes Murcutsont1, Milne Edwards and Jules Haime, Pol. Foss. des Terr. Palzeoz. 
(Arch. du Mus., vol. v), p. 428, 1851. 
Corallum massive, subturbinate; common basal plate covered with a very thick 
39 
