APPENDIX A. (LONSDALE ON CORALS.) 
603 
retain Lhwyd’s name for his own coral, and to apply the new one to Lithost. floriforme \ but as the 
former fossil is little known, and has probably been mistaken, in some cases, for other fossils of similar 
general aspect, yet very different structure, and as Lithost. floriforme is a well-known, strongly marked 
coral and excellently figured by Martin in his ‘ Petrificata Derbiensia’ (pi. 4-3, 1809), though without an 
available name, it was subsequently deemed correct to apply the new term to the obscure fossil, and the 
old term to the one which was well known, and by which geologists have been accustomed to desig- 
nate it. 
The characters by which it is proposed to distinguish Lithostrotion from other lamelliferous Anthozoa 
are the following. 
A coral composed of stems generally coadunated ; interior of stems separable into three differently con- 
structed areas -, 1, a central axis ; 2, an inner zone composed of vertical lamella ; 3, an outer zone formed 
partly of lamella but chiefly of variously arched or vesicular plates : the mode of reproduction was by germs 
developed within the area of the parent stem, or without it by an occasional extension of the polype. 
The specific characters depend upon the difference in the structural details of the three areas. 
By the above descriptive notice, Lithostrotion, it is presumed, will be readily distinguished from the 
uni-areal and non-proliferous Columnaria, to which it has been united by some authors ; from the bi-areal 
though proliferous Cyathophyllum ; and from the uni-areal, subdividing polype, Astrea, with both of 
which it has been also identified. 
Lithostrotion emarciatum. 
Columns irregularly polygonal, outer surface rarely exposed, inner broadly ribbed; axis elliptical, detachable ; 
inner zone bounded outwardly by arched plates, lamella generally of equal breadth ; outer zone very 
vesicular, plates broad slightly convex, not highly inclined, very partially traversed by extensions of 
lamella ; terminal cup not deep ; boss slightly prominent surrounded by a depressed area ; inner zone 
nearly flat, lamella distinct, simple ; bund of outer area highly inclined towards the exterior circum- 
ference, vesicular plates broad, slightly convex;. 
Fig. a. Transverse section, upper surface. 
Fig. b. Transverse section, under surface. 
Fig. c. Magnified portion of under surface to exhibit the characters of the laniell*. 
Fig. d. Vertical section, magnified, to show the internal structure of the axis, and the connexion with the inner zone. 
Fig. e. Vertical section, magnified, to exhibit the perpendicular external and transverse internal characters of the axis, and the nature of the inter- 
stitial plates between the lamellae, also the connexion of the. inner with the vesicular or outer zone. 
Fig. f. An immature column at * within the area of the parent column : the continuous boundary of the latter may be easily traced. 
