The imperfectly understood group of the Monticuliporoids, by some authors placed with the Polyzoa (Order Trepostomata), are well represented in Australia by the genus _Stenopora_ (Fig. 70 F). The corallum is a massive colony of long tubes set side by side and turned outwards, the polyp moving upwards in growth and cutting off the lower part of the tube by platforms like those in the tabulate corals. Some of the species of _Stenopora_, like _S. tasmaniensis_, of New South Wales and Tasmania, are found alike in the Lower and Upper Marine Series. _S. australis_ is confined to the Bowen River Coal-field of Queensland. _Stenopora_ often attains a large size, the corallum reaching over a foot in length. Neither Jurassic or Cretaceous Corals have been found in Australasia, although elsewhere as in Europe and India, the representatives of modern corals are found in some abundance. =Cainozoic Corals.--= In Tertiary times the marine areas of southern Australia were the home of many typical solitary Corals of the group of the Hexacoralla. In the Balcombian beds of Mornington, Victoria, for instance, we have genera such as _Flabellum_, _Placotrochus_, _Sphenotrochus_, _Ceratotrochus_, _Conosmilia_, _Trematotrochus_, _Notophyllia_ and _Balanophyllia_ (Fig. 71). [Illustration: =Fig. 71.--CAINOZOIC CORALS.= 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.