14 TRANSACTIONS OF THE RoyAL CANADIAN INSTITUTE. [VOL. XI 
The corallum is simple and conical, rather strongly curved at first, 
but almost straight in later stages of growth. The length of the con- 
cave side is 35 mm. and that of the convex side 56 mm. measured in a 
straight line from the apex. The diameter from the calyx rim on the 
concave side measured directly across is 27 mm. 
The character of the calyx is somewhat doubtful, but it is probably 
of moderate depth, with a floor disposed at an oblique angle to the 
axis of the corallum. The centre of the floor is marked by a prominent 
elevation representing the extremity of a central zone of reticulated 
tissue. A fossula is probably present, although it was not observed in 
the specimens owing to the calyces being filled with matrix. The ex- 
terior is marked by very delicate transverse lines and faint septal furrows: 
both of these are so obscure that to the naked eye the exterior is quite 
smooth. Increase is effected by calycinal gemmation. 
The transverse section shows a distinct tetrameral arrangement of 
the septa which are apparently of one order only. The thickened 
peripheral ends of the septa form an outer wall 2 mm. thick. It is 
possible that very short secondary septa are hidden in this wall, but no 
trace of their existence was observed. About 50 septa occur at a dia- 
meter of 25 mm. The cardinal septum is largely absorbed, and its 
position is clearly marked by an opening between the adjoining septa. 
On both sides of the cardinal septum the septa are rather short. The 
alar septa are long and the counter septum and those near it are long 
and rather crowded. On the cardinal side the septa do not reach the 
centre, but on the counter side the inner ends of the septa coalesce 
and with the dissepiments build up a zone of reticulated tissue. At a 
point nearer the apex a second transverse section does*not show the 
above characteristic in so distinct a manner, as all the septa extend to 
the central spongy zone. Here also the septa are united by occasional 
curved dissepiments. Plate V, Fig. 2. 
A tangential section shows the septa and the numerous downwardly 
arched dissepiments. Plate V, Fig. 3. 
Median vertical sections show that the dissepiments are moderately 
flat or convex in the peripheral region, but that they turn upwards to 
join the central reticulated area. Plate V, Fig. 1 shows a considerable 
difference on the two sides: the right is the cardinal and the left the 
counter sides. The difference is in part due to the fact that the section 
is almost in the line of a septum on the left side, while on the right the 
septa are cut at a low angle. 
This form is undoubtedly near S. corniculum, Hall, and I should 
ascribe it to that species except for the following points of difference: 
the smooth exterior, the absence of secondary septa, and the presence 
