APPENDIX A. (LONSDALE ON CORALS.) 
605 
(2.) The lamellae of the inner zone had, apparently, a continuous, vertical range throughout the column. 
For a short distance from the axis, each consisted of a single plate (figs, b, c), and then swelling out 
more or less abruptly divided into two layers, the outer pairs of which were united at the circumference 
of the zone by curved extensions. In some few instances, very narrow, secondary or intermediate la- 
mellae occurred, formed also of two layers, similarly connected to the proximate broad plates. Without 
the regular limits of this inner zone, fractured surfaces often exhibited curved edges between partial 
lamellae, both being intersections of the component parts of the exterior area (figs, a, c). The interstitial 
laminae of the inner zone (figs, d, e), though in general more or less waved, were, for the greater part, 
horizontally arranged, but they were sometimes highly inclined, and the variations in their position pro- 
duced a great irregularity of character in transverse fractures. 
(3.) The arched or vaulted plates, which composed the outer area, sprung from the lamelliferous zone 
in a somewhat, similar manner to the acanthus leaves of a Corinthian capital ; but they were variously 
united and reticulated in their range towards the periphery. On the under surface (fig. b) they were more or 
less distinctly traversed by faint grooves and intermediate slightly convex bands ; the former being prolonged 
indications of the fine divisional spaces between the two plates of the lamellae ; and the latter, of the arches 
by which the opposite plates were united. The upper surface (figs, a,f ) of these bladder-like or vesicular 
laminae was almost invariably so concealed by a coating of crystallized carbonate of lime, that minor struc- 
tural details were not ascertainable. The vertically discontinuous lamellae, by which they were more or less 
traversed, were curved on the upper or free edge, resembling segments of circles ; and their range towards 
the periphery of the column was generally very limited, though in some few instances equal to the whole 
breadth of the area. They sprung, apparently with rare exceptions, from the narrow interval between 
the subdivided plates of the primary lamellae ; and were probably connected with them, vertical sections 
of the inner zone exhibiting only outer sides of the plates, crossed by fractured edges of the interstitial 
laminae. 
The single terminal cup which was examined, was seated within the body of the largest specimen, 
and completely over-arched by the growth of other columns. It required no particular observation. 
The whole of the lamellae and plates forming the internal structure of the coral, as well as the walls, 
were apparently imperforated. 
Cases of young columns springing within the area of those fully developed, were sufficiently numerous 
to prove the essential mode of reproduction, and an illustrative example is given in fig. f, at the part 
marked with an asterisk. English specimens of Lithost. floriforme, which permitted polished sections 
to be made, exhibited every stage of development from the germ with an imperfect boundary, and 
scarcely a trace of lamellae, through all the intermediate gradations to the perfect, fully constructed 
column with distinct solid walls. The germs always appeared among the vesicular plates near the inner 
margin of the parent column, but not in immediate connexion with the wall, and the rudimentary lamellae, 
converging from an imperfect periphery, could not be referred, even in part, to the lamellae of the old 
column. This statement is necessary to prevent the suspicion that the young columns of Lithostrotion 
were produced by a subdivision of the parent polype, as in the true Astreae of Ehrenberg. 
In the specimens of Lithost. emarciatum, examined by the describer, no cases were observed of inter- 
polated columns, produced by an extension of the germ-bearing portion of the polype, over an interval 
arising from accident or irregular growth in the coral. 
Locality and Formation.— Borovitchi, near Valdai. Carboniferous limestone. 
