37 
present was accoimtecl for by Prof. H. A. Nicholson and the WriteP on the 
supposition that the tal)ulce, in the first place, were perforate, and in the 
second, incomplete. The facts, however, detailed above, and those to be given 
later under the heading “ tabulse,” do not appear to bear out this opinion, 
which, I think, must be abandoned. I can, after a further and more extensive 
acquaintance with Stenopora, only arrive at the conclusion that this peculiar 
investment, in spite of its extraordinary development, is principally of 
inorganic origin, and is produced by a post-mortem deposition within the 
cavities of the tubes, as indicated by its presence in some examples and not 
in others.^ 
The proper wall in its unthickened state is exceedingly uniform in 
appearance and thickness, and is usually visible as a dark line, so thin and 
structureless as to render any subdivision between contiguous corallites 
perfectly imperceptible, and thus resembling such Monticuliporoids as Moriti- 
ciilipora (Diplotrypa) petrop)olitana. Pander, sp.^ This apj)earance is par- 
ticularly characteristic of Tasmanian specimens, but in no Australian example 
have I met with that peculiar disintegration into dots, resembling a string of 
beads, figured by Waagen and Wentzel in the walls of the Indian variety of 
S. ovata.'^ Nor has the slightest indication presented itself of such wall- 
structure as characterises Moniiculipora (KeterotrypaJ ramosa, D’Orb.,^ 
wherein each visceral chamber is enclosed by a dark line or marginal ring, 
usually circular or oval in outline, marking the original boundary of the tube, 
and the interspaces between these dark lines filled in by selerenchyma of a 
different texture and much lighter colour. 
It has been suj)posed by Prof. II. A. Nicholson that in the Monticuli- 
poridic each tube or corallitc theoretically possesses a perfectly independent 
and complete wall,* *^ that is, of two thin lamimc adpressed, each apj:)ertaining 
to a separate corallite. Theoretically, no doubt, this view of the Monticuli- 
poroid wall-structure is strictly accurate, but in Stenopora I have quite 
failed to detect, by direct microscopic examination, except in S. crinita, any 
bilaminar structure in its walls, as also did Messrs. Waagen & W’entzel.^ 
' Ann. Mag. Nat. Hist., 1886, XVII, p. 176. 
^ As a further proof of this, I may mention that a specimen of S. crinita has recently come before me from 
the Wollongong District, in which the corallites are almost completely destitute of secondary deposit. This is of 
great importance, from the fact that Wollongong is amongst the localities which have yielded the best specimens 
showing the secondary deposit. 
’ Nicholson, Genus Monticulipora, &c., 1881, p. 37, f. lA. 
* Pal. Indica, Salt Eange Fossils, 1886, Vol. I, Part 6, t. 110, f. Ic. 
* Nicholson, toe. cit., p. 39, p. 37, f. 1 b. 
® Nicholson, loc. cit., p. .36. 
’’ Pal. Indica, Salt Range Fossils, 1886, Vol. I, Part 6, p. 863. 
