117 
Height of corallum figured (young example), 9 mm.; diameters 
of its calice, 7 and 6 mm. respectively ; diameters of calice 
figured (aged example), longest 10°5 mm., shortest 9 mm. In the 
corallum of the latter the base is broken off, but the remaining 
portion is still 11 mm. high. 
Locality.—Table Cape, Tasmania (Eocene). Fairly common, 
but usually worn. Collected by Professor Tate and J. Dennant. 
This coral much resembles P. swpracostatus, mibi. Its morc 
exsert septa and difference in shape entitle it, I think, to specitie 
rank. 
GENUS STEPHANOTROCHUS, Moseley, 1881. 
Corallum dense and compact in substance, cup-shaped or 
saucer-shaped, with trace of early attachment, usually with well- 
developed costz, bearing a succession of small spines, with widely 
open capacious fossa. Septa usually extremely exsert, the exsert 
quinaries, or quaternaries, where these are not present, lying 
next to the primaries, higher than the tertiaries or equal to them. 
Columella absent or little prominent. 
Four species of corals dredged by the Challenger Expedition, 
viz., three in the Atlantic and one off the coast of New South 
Wales, were at first referred by Professor Moseley to the genus 
Ceratotrochus. In his later special Monograph, however, he 
instituted the above genus for their reception. I have now to 
draw attention to a fossil coral from the Australian Eocene, 
which exhibits the essential characteristics of Moseley’s genus. 
Stephanotrochus Tatei, spec. nov. PI. iii., figs. 1 a, b, c. 
The corallum is saucer-shaped, but so shallow as to be almost 
discoia. Adult examples are compact in substance and free, but 
younger ones, besides being much thinner, show a small, rounded, 
and slightly depressed scar of former attachment. 
The base is flat and roughly hexagonal in outline. The 
hexagonal angles are opposite the primary coste, from each of 
which a long, stout, but gradually tapering spine projects 
obliquely downward (approximate angle with base, 145°), so that 
the coral when placed upon a flat surface rests on the points of 
six equidistant spiny processes. The basal edges bend gently 
round to form the wall of the corallum at an angle which varies 
in different individuals from 45° to about 60°. The voste, which 
are continuations of the septa, are prominent on the sides of the 
corallum, and covered with transverse rows of granules, which 
give them a serrated appearance. On the base they are either 
obsolete or just traceable as slightly raised lines, the primaries 
and secondaries being more persistent than the rest. (It should 
be noted that the parallel bars shown in the centre of the base 
figured have no significance, and are absent in similarly worn 
