33 
Septa obsolete. Tabiilse remote, usually placed at corresponding levels in. 
contiguous tubes, but at irregular distances within the same tube, generally 
complete, but soihetimes perforate, especially at the final period of growth of 
the corallites, when the calices at times appear with their terminations closed 
by a perforated lid. Mural pores absent. The massive forms usually have the 
corallites constricted at intervals on the same level, representing periodic 
stages of growth, and giving to the entire mass a stratified appearance. 
Gemmation intermural. 
Ohs . — The corallum in Stenopora is usually more or less branched, 
but the branches may be so thick, or may so extensively coalesce, that its 
general form becomes that of a lobate mass. The corallites radiate in all 
directions from an imaginary axis, and present very different appearances in 
the central and circumferential portions of the corallum respectively. In 
the central or axial portion the tubes arc nearly vertical, essentially polygonal 
or prismatic in shape, have thin walls, and arc nearly or quite in contact 
with one another throughout. As they pass upwards the tubes gradually 
diverge, coming at last to be nearly horizontal, and preserving this direction 
for a considerable distance, till they at last open upon the surface. There is 
thus an exterior zone of the corallum, in which the corallites are nearly 
transverse to the axis of the branches, and in this region they have a generally 
cylindrical appearance. We are too little acquainted with the perfect 
corallum in the majority of species to speak definitely as to its ultimate 
outline in each one. Stenopora ovata, S. Leichhardti, S. australis^ and 
S. tasmaniensis are all ramose species so far as we know them, but I have 
reason to suspect that the first three, in this condition, are but the terminal 
and younger portions of much more massive coralla, perhaps arising from 
coalesced branches, but hardly, I think, from definitely-grown lobate masses 
like S. crinita. It will be shown further on that even this species does at 
times shoot forth from its otherwise undulating and semi-mammillated 
surface out-growths of a ramose character. I have been favoured by Mr. E. 
M. Johnston, P.L.S., of Hobart, with a Tasmanian foliated Stenopora, the 
corallum growing in rather undulating tabular or foliated expansions, like 
that of Chcetetes hyperhoreus, N. & E.,’^ the corallites opening on the free 
lateral surfaces, and arising from a median line, and imaginary axis.^ 
* Nicholson & Etheridge, Junr., Proc. Linn. Soc. (Zool.), 1878, XIII, p. 367. 
^ Two such forms of growth have already been mentioned by Prof. H. A. Nicholson and the Writer, both 
from Tasmania, and now in the British Museum. The microscopic structure of one was compared to that of 
ovata ; the other, “ a remarkable frondescent specimen,” was compared to X tasmaniensis. 
