ON THE STRUCTURE OF CARBONirEROUS CORALS. 165 



Sixth Report of the Committee, consisting of the Rev. Thomas Wilt- 

 shire, M.A., F.G.S., Prof. Williamson, F.R.S., and James 

 Thomson, F.G.S., Secretary, appointed to investigate the Structure 

 of the Carboniferous Corals. 



During the past year the Committee have conducted their investigations 

 and have made sections of upwards of 300 specimens. In order that they 

 might arrive at as clear a conception as possible of their specific value, the 

 Secretary went over to Paris, and examined the types of MM. Milne-Edwards 

 and J. Haimc, and also those of Prof, do Koninck in Belgium, and compared 

 them with the structural details as delineated in the Plates already prepared ; 

 and the result of his investigation warrants them in saying that they are glad 

 they have not published more than brief abstracts of their investigations. The 

 delay has also enabled them to try several methods for delineating the intri- 

 cate and delicate structure of many of these corals, well knowing that their 

 structure could not be reproduced by the ordinary process of lithograph}-. 

 The system adopted is the result of many experiments, and the one most 

 suited for the purpose, as by it can be given facsimiles of the most delicate 

 stnicture, thus placing in the hands of students the means whereby they can 

 name either genera or sj^ecies even from small fragments. 



The results of the investigations and comparison of the type forms referred 

 to point to three new genera. The varieties, however, are so numerous, 

 that it was felt desirable to make other sections before determining distinct 

 varieties. 



The following have been determined, and arc engraved upon what they 

 l^rovisionally term Plate XII. 



AsindiophyUum, Thomson, gen. nov. The generic name is taken from 

 the form and position of the boss in the centre of the calice, it being helmet- 

 shaped. As the characters upon which the generic distinction is founded 

 have been described in detail in the Transactions of the Philosophical Society 

 of Glasgow for 1874, the descriptions need not be repeated. The generic 

 and specific names of those published are : — 



Pigs. 1 & lA. Aapidiophi/lluni Koniiiclianum, Thomson, sp. nov. 



2. „ Hihvlni/ianvm, Thom., sp. nov. 



3. „ Henncdii, Thom., sp. nov. 



4. „ cniciforme, Thom., sp. nov. 

 5 & 5A. „ elegans, Thom., sp. nov. 



In Aspidioplnjllum HuxJeyiannm one of the primary septa is shorter than 

 the others, with a clavate tube-like process lying in the plane of the open 

 interseptal spaces. Around the inner margin of the tube-like body are 

 grouped a number of ovule-like bodies, much resembling ova. Detailed 

 accounts of these are published in the Transactions of the Philosophicsi 

 Society of Glasgow for 1874. 



Plate XII. figs. 10, 11, 12, 14, 15, and 16 belong to the same genus, but 

 differ from those described in essential specific characters, and will be described 

 hereafter. 



Plate XIII. contains representations of seven species of the genus Elwdo- 

 phyllum, Thomson, gen. nov., which Lave been described in the ' Geological 

 Magazine,' viz. : — 



