203 
of the tubes, and as many unthickened segments, occupy the space of one line. 
Tabula) horizontal, sometimes comjjlete, or at other times perforated by a central 
aperture, remote from one another as a general rule, and, for the most part, placed at 
corresponding levels in contiguous tubes, these levels haying no evident relation to the 
annular thickenings of the tubes ; acanthoporos wanting. 
Obs. The original specimens from the Bowen Itiver Coal Pield did not exhibit the 
surface in any manner that would enable the external characters of the species to be 
described. In identifying them with j8. ovata, Lonsdale, we formerly relied chieEy upon 
the rapid divergence of the tubes from the central bundle, and the great number and 
close arrangement of the annular thickenings of the corallites in the horizontal portion 
of their course, these being sometimes so much developed as to give to the exterior of 
the tubes a regularly crenulated appearance. The annular thickenings are also 
nnusually broad ; and many smaller tubes are interpolated among the larger ones as the 
surface is approached. 
In its minute structure, however, the present species differs widely from S. ovata^ 
and resembles no other species of the genus known to us. One of the most marked 
characters of S, australis^ in which it seems to stand alone among the species of 
^ictiopora, is the total absence of acanthopores (PI. 6, fig. 7). This character at once 
distinguishes the species from S. omta, Lonsd. It agrees with the latter in the fact 
that the walls of contiguous corallites are completely amalgamated, the primordial wall 
only being visible in the axis of the branches, and also in the average size of the tubes ; 
cut the corallites are mostly more of a polygonal tha7i of a simply rounded shape. As 
®een in longitudinal sections (PI. G, figs. 6 and 8), the corallites are thickened periodically, 
the peripheral region of the corallum, by very regular fusiform thickenings placed at 
Corresponding levels in contiguous tubes, as are also the tabula). As seen in long 
lections, the tabula) appear to be complete ; but, as viewed in tangential sections, 
^Ppearances are seen which are difficult to explain, except upon the supposition that 
ce tabula) arc perforated by a central aperture (PI. 6, fig. 7). Thus in many of the 
corallites, as seen in tangential sections, wo observe a broad ring of light-coloured 
^clerenchyma internal to the proper walls of the tube, and enclosing a central rounded 
^Perture. What this ring is, unless it be a perforated tabula, it is difficult to see ; but 
lere is the curious feature that it is usually separated from the true wall for a portion 
ct Its extent on one side of the tube. 
, our former description of this sjiecies (loc. cit.') we described and figured the 
ove-inontioned singular structures, but were unable to give any explanation of their 
a ure, as we believed the tabuhe to be imperforate. Wo are obliged to admit, however, 
)at if this be their real nature they differ in some inexplicable points from ordinary 
oiated tabula). In Stenopora IToiusti, Nich., the tabula) ai’e not only perforated by 
apertures, but this fact is quite as easily recognizable in long sections as in 
St ones. In this form, however, the tabula) arc extremely numerous and the 
® preservation is also very good. Mr. John Young has proposed the generic name 
for a coral allied to or identical with Stenopora Roivsii. In all other 
^^spects, however, save as regards its perforated tabuloe, S. Ilowsii does not differ from 
tab species of Stenopora. If no other species of Stenopora possessed perforated 
Perh'^’ 'voiild be ground for accepting Tabulipora as a sub-genus of Stenopora, or 
oc distinct genus. If, on the other hand, the structures above described as 
ill S. australis are really perforated tabula), there does not seem to bo any need 
tal generic name. Moreover, it is only on the supposition that perforated 
ass * °®cur ill the species of Stenopora generally, that we can account for Lonsdale’s 
ion that the mouths of the corallites in this genus are “ closed at the final period 
