56 
GENUS PLATYTROCHUS. 
Platytrochus Maudensis, spec. nov. PI. xxii., figs. ба, b. 
Corallum minute, free, and much compressed, especially 
inferiorly. The lateral edges of the faces descend vertically 
for rather more than halfway from the summit, when they 
curve towards each other and meet in a roundly pointed 
base.  'The upper part of the corallum thus forms a rect- 
angle and the lower a triangle, with the base as its apex. 
A white, shining epitheca covers the whole surface. Be- 
neath it the coste, which correspond with the septa, usually, 
but not always, show as broad, flat bands, with narrow 
interspaces; in the figured example they are exceptionally 
well marked for a short distance from the summit. 
The calice is arched and higher centrally than at the 
wall It is elliptical with the two axes in the ratio of 10 to 
6. The septa curve upwards from the wall to their central 
terminations. They are granular, equal, and in six sys- 
tems with three cycles. In the extreme lateral systems the 
tertiaries curve towards the primaries, and join them close 
to the columella; in the other systems this union is rarely 
seen. The secondary septa are always free. The columella 
is strong, nodular, and occupies a considerable space in the 
calice. In the type it consists mainly of three projecting 
nodules fused together by solid tissue; in other examples its 
outline is irregular and differs in every individual. There 
is, however, always a central linear portion which is joined 
by processes from the septal ends. One specimen, cut trans- 
versely a short distance below the upper surface of the calice, 
is solid centrally, the columella being completely fused with 
the axial margins of the septa. 
Height of corallum, 45 mm.; length of calice, 25 mm.: 
breadth of do., 1:5 mm. The specimens are uniform in size. 
Locality, etc.—Fairly common in the lower beds at Maude, 
on the Moorabool River (seven examples). These beds are 
usually classed as Eocene. 
The corallum of this small species looks much like a worn 
P. hastatus with the spear-like base removed. Its calice, how- 
ever, is nearer that of P. curvatus. Тһе papilli of the colu- 
mella, which characterise the genus Platytrochus, are, I 
think, in the Maude coral soldered into groups by secondary 
infilling. 
GENUS CERATOTROCHUS, 
Ceratotrochus Australiensis, Duncan (var.). Pl. xxii., figs. 5a, б. 
Conotrochus typus, Seguenza, var. Australiensis, Duncan, 
(90701. Vol, SL pp. 298 0. Ph жік, ДО 8) 
This coral, which is very common in the Australian ter- 
tiaries, differs in several respects from that described by Se- 
