A—Flabellum victoriae, Duncan. Balcombian. Mornington, Vict.
B—Placotrochus deltoideus, Dunc. Balcombian. Muddy Creek, Hamilton, Vic.
C—Balanophyllia seminuda, Dunc. Balcombian. Muddy Creek, Hamilton, Vic.
D—Stephanotrochus tatei, Dennant. Janjukian. Torquay, near Geelong, Vict.
E—Thamnastraea sera, Duncan. Janjukian. Table Cape, Tas.
F—Graphularia senescens. Tate sp. Janjukian. Waurn Ponds, near Geelong, Vic.
G—Trematotrochus clarkii, Dennant. Kalimnan. Gippsland Lakes, Vic.
Corals especially characteristic of the Janjukian Series are Paracyathus tasmanicus, Stephanotrochus tatei, Montlivaltia variformis, Thamnastraea sera and Dendrophyllia epithecata. The stony axis of the Sea-pen, Graphularia senescens, a member of the Octocoralla, is also typical of this stage, and are called “square-bones” by the quarrymen at Waurn Ponds, near Geelong, where these fossils occur.
The Kalimnan Corals are not so abundantly represented as in the foregoing stages, but certain species of Flabellum and Trematotrochus, as F. curtum and T. clarkii, are peculiar to those beds. Several of the Janjukian Corals persist into Kalimnan times, some dating as far back as the Balcombian, as Sphenotrochus emarciatus. The Sea-pen, Graphularia senescens is again found at this higher horizon, at Beaumaris; it probably represents a varietal form, the axis being smaller and more slender.
Other examples of the Octocoralla are seen in Mopsea, two species of which are found in the Janjukian at Cape Otway; the deeper beds of the Mallee; and the Mount Gambier Series.
A species of the Astraeidae (Star-corals) of the reef-forming section, Plesiastraea st.vincenti, is found in the Kalimnan of Hallett’s Cove, South Australia.
HYDROZOA.
The few animals of this group met with in fossil faunas are represented by the living Millepora (abundant as a coral reef organism), Hydractinia (parasitic on shells, etc.), and Sertularia (Sea-firs).
Milleporids and Stylasterids.—
Although so abundant at the present time, the genus Millepora does not date back beyond the Pleistocene. The Eocene genus Axopora is supposed to belong here, but is not Australian. Of the Stylasterids one example is seen in Deontopora, represented by the branchlets of D. mooraboolensis, from the Janjukian limestone of the Moorabool Valley, near Geelong.
Hydractinia.—