444 Royal Society. 



PEOCEEDIXGS OF LEAEXED SOCIETIES. 



ROYAL SOCIETY. 



May 4, 1871. — Sir Pliilip Grey-Egerton, Bart., Yice-President, 

 in the Chair. 



" On the Structure and Affinities of Gitynia annulaia, Dune, 

 with Eemarks upon the persistence of Palaeozoic Types of Madre- 

 poraria." By P. Maktix DrNCAN, M.B. Lend., F.K.S., Professor of 

 Geology in King's College, London. 



The dredging-expedition which searched the sea-floor in the track 

 of the Gulf-stream of 1868, yielded, amongst other interesting 

 Madreporaria, a form which has been described by Count Pourtales 

 under the name of Haplophyllia paradoxa, and which was decided 

 by him to belong to the section Rugosa. 



The last expedition of the ' Porcupine,' under the supervision 

 of Dr. Carpenter, F.R.S., and jNIr. J. Gwyn Jeffreys, F.R.S., ob- 

 tained, off the Adventure Bank in the Mediterranean, many speci- 

 mens of a coral which has very remarkable structures and affinities. 

 The species is described under the name of Guynia annulata. Dune. 

 The necessity of including it amongst the Rugosa and in the same 

 family, the Cyathoxonidce, as Haplophyllia paradoxa is shown. 



Having this proof of the persistence of the rugose type from 

 the Palaeozoic seas to the present, the affinities of some so-called 

 anomalous genera of Midtertiary and Secondary deposits are cri- 

 tically examined. The Australian tertiary genus Conosmilia, three 

 of whose species have strong structural resemblance to the Ru- 

 gosa, is determined to be allied to the StauridcB, and especially to 

 the Permian genus Polycoelia. The Secondary and Tertiary genera 

 with hexameral, octomeral, or tetrameral and decameral septal ar- 

 rangements are noticed, and the rugose characteristics of many 

 lower Liassic and Rhsetic species are examined. 



The impossibility of maintaining the distinctness of the Palaeo- 

 zoic and Neozoic coral-faunas is asserted ; and it is attempted to 

 prove that whilst some rugose types have persisted, hexameral 

 types have originated from others, and have occasionally reverted 

 to the original tetrameral or octomeral types, and that the species 

 of corals with the confused and irregular septal members so cha- 

 racteristic of the lowest Neozoic strata descended from those Rugosa 

 which have an indefinite arrangement of the septa. 



The relation between the Australian Tertiary and recent faunas, 

 and those of the later Palaeozoic and early Neozoic in Europe, is 

 noticed, and also the long-continued biological alliances between the 

 coral-faunas of the two sides of the Atlantic Ocean. 



