A--Protospongia reticulata, T. S. Hall. Low. Ordovician. Bendigo. B--Receptaculites fergusoni, Chapm. Silurian. Wombat Creek, Vict. C--R. australis, Salter. (Section of wall, etched, after Eth. & Dun) Mid. Devonian. Co. Murray, N.S.W. D--Protopharetra scoulari, Eth. fil. Cambrian. S.A. ] Another genus of Sponges, _Hyalostelia_, whose affinities are not very clear, occurs in the South Australian Cambrian at Curramulka. This type is represented by the long, slightly bent, rod-like spicules of the root-tuft, and the skeletal spicules with six rays, one of which is much elongated. _Stephanella maccoyi_ is a Monactinellid sponge, found in the Lower Ordovician (Bendigo Series) of Bendigo, Victoria. =Silurian Sponges.--= Numerous Sponges of Silurian age are found in the neighbourhood of Yass, New South Wales, which belong to the Lithistid group, having irregular, knotty and branching spicules. These sponges resemble certain fossil fruits, generally like diminutive melons; their peculiar spicular structure, however, is usually visible on the outside of the fossil, especially in weathered specimens. The commonest genus is _Carpospongia_. =Receptaculites: Silurian to Carboniferous.--= In Upper Silurian, Devonian, and Carboniferous times the curious saucer- or funnel-shaped bodies known as _Receptaculites_ must have been fairly abundant in Australia, judging by their frequent occurrence as fossils. They are found as impressions or moulds and casts in some of the mudstones and limestones of Silurian age in Victoria, as at Loyola and Wombat Creek, in west and north-east Gippsland respectively. In the Devonian limestones of New South Wales they occur at Fernbrook, near Mudgee, at the Goodradigbee River, and at Cavan, near Yass; also in beds of the same age in Victoria, at Bindi, and Buchan (Fig. 67, B.C.). _Receptaculites_ also occur in the Star Beds of Upper Devonian or Lower Carboniferous age in Queensland, at Mount Wyatt. It will thus be seen that this genus has an extensive geological range. =Carbopermian Sponges.--= A Monactinellid Sponge, provisionally referred to _Lasiocladia_, has been described from the Gympie beds of the Rockhampton District, Queensland. _Lasiocladia_, as well as the Hexactinellid Sponge _Hyalostelia_, occurs in the Carbopermian of New South Wales. =Cretaceous Sponges.--= No sponge-remains seem to occur above the Carbopermian in Australia until we reach the Cretaceous rocks. In the Lower Cretaceous series in Queensland a doubtful member of the Hexactinellid group is found, namely, _Purisiphonia clarkei_. In the Upper Cretaceous of the Darling Downs District pyritized Sponges occur which have been referred to the genus _Siphonia_, a member of the Lithistid group, well known in the Cretaceous of Europe. =Cainozoic Sponges.--=