292 THE PROCEEDINGS OF THE LINNEAN SOCIETY On the Bxtratropical Corals of Australia. By the Rev. J. E. Tenison-Woods, F.G.S., F.L.S., Cor. Mem. Linn. Soc, N. S. W. ; Hon. Mem. Royal Soc, N. S. W., Victoria, Tasmania, &c., &c. Plates IV., V., & VI. The Madreporaria or stony corals have two very distinct and very diverse habitats. One is for the most part tropical, the corals forming immense masses or reefs which form barriers, islands, fringing reefs, &c., of such extent as to occupy a very large and important portion of the surface of the Globe. The other is the home of small, simple or compound corals which live on the floor of the ocean in areas remote from coral reefs, and at all tempe-ratures and depths even as much as 800 fathoms. The dredgings of the " Lightning," " Porcupine," " Challenger," and that of M. de Pourtales in the Gulf Stream, have made known a great number of these hidden forms of life. They have also cleared up many of the obscurities which a limited knowledge of species necessarily gave rise to. They have largely increased the list of both genera and species of corals. They have shown some of the extent to which variation affects those already known, thus uniting many forms hitherto regarded as distinct. Up to this time however, all these discoveries have had but little effect on the knowledge of Australian forms. It is true that the " Chal-lenger" has visited these seas, but with what result may not be known for a long time. I may say that the extratropical Madre-poraria of Australia have been literally untouched. Yet a special interest is attached to them on account of what has been made known through geological researches. It has been ascertained that our Eocene and Lower Miocene strata are particularly rich in the kind of corals with which we have to deal. As a test for the age and relations of the deposits no fossils could be more suitable. So far as they had been studied they have led to remarkable results. We have to thank Professor Duncan for being the first to enter upon the field. His industry and pains-taking care, together with his almost unrivalled knowledge and experience in this department have been devoted to the subject,
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