APPENDIX A. 
(LONSDALE ON CORALS.) 
621 
community of existence, and as the walls of the adjacent stems are also inseparable, there are marked 
generic distinctions from Lhwyd’s coral. With Ehrcnberg’s Caryophyllia, including the Lobophyllia of 
De Blainville, there is a greater agreement, each polype having at the superior termination a perfectly 
distinct boundary, and in general considerable intervals between it and those next adjacent; but internally 
the structure of the Bristol coral and others allied to it, is so very distinct from that of Caryophyllia, par- 
ticularly in the bi-plated nature of the lamella? and in the vesicular character of the interstitial plates, as 
to warrant, independent of the mode of grouping and the decided continuation on the outer side of the 
divided stems, of the lamellae of the undivided, a generic separation. 
It is proposed, therefore, to apply to Lhwyd’s coral the generic designation of Stylastraea ( orvXos , co- 
lumna ; iirrrpov, astrum ), recommended to the describer by Mr. Murchison on account of its columnar 
aspect ; and if Parkinson be correct in considering it as identical with a fossil described by Volkmann, it 
is further suggested that it should be distinguished from other species by the designation of Stylastraa 
vorticalis. (Parkinson, Org. Rem., vol. ii. p. 45.) 
The following may be given as a summary of the generic characters, so far as the nature of the coral 
is known to the describer : — 
A columnar , lamelliferous, stony poly pidom; lamella exceeding twelve, bi-plated; columns closely aggregated, 
easily separated ; internal structure twofold, — 1st, u central area occupied by variously blended lamella or 
contorted lamina, without a distinct, persistent axis ; ‘2nd, cm outer zone, traversed by vertical, continuous, 
bi-plated lamella, not fasciculated ; interstices occupied by numerous, arched or vesicular lamina; additional 
columns produced by subdivisions of the parent column; polypes perfectly circumscribed at the superior termi- 
nation ; no connecting mantle. 
Stylus Irma inconferta, sp. n. 
Columns 4 — 6-sided, irregular in the breadth of the planes and the range upwards ; outer surface unequally 
ribbed; central area, variously contorted lamina ; outer zone, lamella about thirty -four, alternately broad 
and very narrow; interstitial plates numerous ; terminal cup not observed; additional columns bi-partite 
(only?). (PI. A. fig. 2.) 
This fossil differs from Lhwyd’s species in the greater dimensions of the columns, in the more open 
structure of the interior, and in the centre being much less occupied by prolongations of the lamellm. 
The specimen of Styl. inconferta which was examined, was a fragment detached from the interior of a 
mass, and it measured about four inches and a half in altitude, two and a quarter in width, and one and a 
half in extreme thickness. The columns exhibited not the slightest indications of divergence, but they 
were more or less irregular in form and range, and so perfectly moulded to each other as to indicate a 
complete aptitude in the polypes to fill every interspace (fig. 2). They had in some places been fractured, 
and occasionally dislocated, apparently during the life of the animal ; and at the upper extremity the whole 
mass of the specimen, to the depth of half an inch, had so far undergone decomposition, that it presented 
only a confused aggregate of broken plates with slight traces of polygonal boundaries. The average 
diameter of the more regular columns was four lines. 
1. The central area, which was circular and rarely exceeded one line in diameter, had no definite boun- 
dary, and was composed of irregular lamina? variously inclined and intermingled, but sometimes, though 
rarely, extended transversely across the area, giving such limited vertical sections very much the aspect 
of the interior of a Cyathophyllum : the general structure, however, agreed more nearly with that of a 
Litliodendron without an axis. Rough transverse sections, moreover, never gave a centre composed of a 
smooth, flat disc similar to that of Cyathophyllum ; and such surfaces, when polished, always exhibited 
faint curved lines, without any symmetrical structure, indicative of the axis of Lithostrotion or Lithe • 
dendron. 
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