68 
The calice is cireular and convex. The septa are stout, 
subequal, and in six systems with four cycles, the last three 
of which form the deltoid combinations usual in the genus. 
The primaries are free, the tertiaries bend towards and join 
the secondaries at a fourth from the columella, and the qua- 
ternaries again join the tertiaries about halfway from the 
margin. At their junction with the next higher orders of 
septa both the tertiaries and secondaries become slightly 
thicker than before, and rise in the calice as rounded, lamel- 
lar, fan-like projections. The raised secondary fans descend 
vertically in the axial space until they reach the level of the 
sunken primary septa, when, similarly with these, they unite 
by thin processes with the columella. The sides of the septa 
are characteristically marked by inwardly converging rows of 
sharp, prominent ribs, which project beyond the free septal 
edges, and strongly dentate them. Sometimes these ribs con- 
sist of intermittent lines, and then resemble rows of sharply 
pointed granules. The columella is strong, lamellar, dentate 
on its free edge, and in line with two opposite primary septa. 
There are usually three dentations on its surface, of which the 
central one rises above the other two. 
The synapticule are numerous, stout, in four or five con- 
centric lines, and placed between all adjoining septa. 
The figured specimen, which is the largest collected, is 13 
mm. in diameter. Its height to the summit of the secondary 
and tertiary fans is 5 mm. The other examples are about 
10 mm. in diameter. 
Locality, ete.—Fairly common in Eocene strata at Spring 
Creek, near Geelong. Rare at Fishing Point, Aire River. - 
This coral is closely allied to Bathyactis lens, Duncan,* 
from which it differs by its larger size, more numerous synap- 
ticule, and stout lamellar columella. In his original descrip- 
tion of B. (Antillia) lens Duncan gives it a small essential 
columella, but when dealing with the same coral under the 
name of Montlivaitia discus Woods states that 1t is without a 
columella. I have examined numerous examples of Duncan’s 
and Woods’s species, and judge that it has a minute, almost 
styliform, columella. 
FAMILY EUPSAMMID 4. 
XENUS BALANOPHYLLIA. 
Balanophyllia truncata, spec nov. Pl. xxv., figs. 4a, b. 
The corallum is simple, short, stout, sub-cylindrical, and 
abruptly terminated superiorly. The base is broad, flat, 
* Antillia lens, Duncan. Ann. and Mag. Nat. Hist., 1865. 
Montlivaltia discus, Ten.-Woods. R.S.N.S.W., 1878.  Bathyac- 
tis lens, Dennant. R.S.N.S.W., 1897. 
