194 11. E. TOMES ON THE GREAT-OOLITE MADREPORARIA. 



of the two genera Cyathophora and Cryptoccenia as proposed by 

 d'Orbigny and afterwards adopted ~by M. de Fromentel. The defini- 

 tion, however, of the two genera requires, in ray opinion, some modifi- 

 cation, which I give as follows : — 



Cyathophora. Coenenchyma small in quantity and dense. Gemma- 

 tion proceeding from it in close proximity to the walls of the corallites, 

 if not actually from the walls themselves. Septa feebly developed, 

 and the cycles not traceable. Calices generally much crowded, 

 appearing at many heights, often oblique, oval, or even polygonal. 



Cryptoccenia. Coenenchyma abundant, and of a loose nature, 

 composed of a great many dissepimental tabulae, from which gemma- 

 tion takes place quite distinct from the walls of the corallites. 

 Septa well developed, and their cycles distinct. The calices not 

 crowded, always round, and on the same level. 



Ctathophoea Botjrgtteti, Defr. sp. Plate VII. figs. 3, 4. 



Astrcsa Bourgueti, Defr. Diet, des Sci. Nat. t. xlii. p. 380 (1826). 

 Cyathophora Richardi, Mich. Icon. p. 104, pi. 2Q. fig. 1 (1843). 

 Cyathophora solida, Phill. Geol. Oxf. and Thames Valley, pi. ii. 



%. 1. 



This coral, which is identical with the one I introduced into the 

 British list in the sixth volume of the Proceedings of the Geologists' 

 Association, from the examination of a single specimen supposed to 

 have come from Garsington, Oxfordshire, occurs in great abundance 

 in the railway-cutting near Stonesfield, but is there confined to the 

 lower parts of the coralliferous layer, and is not, so far as I have 

 been able to observe, associated with any other coral. I now 

 entertain but little doubt, from the appearance of the supposed 

 Garsington specimen, that it really came from Stonesfield. It is no 

 doubt also identical with the species mentioned by Professor Phillips, 

 in his work on the Geology of Oxford and the Thames Valley, under 

 the name Cyathophora solida. 



In young examples the corallites are directed so many ways as 

 to suggest that they grow out of each other ; but in the larger 

 individuals they are often packed closely side by side, and the 

 calices squeezed into an elongated or polygonal form. In the latter 

 case there is hardly any coenenchyma ; but before they have attained 

 to a considerable growth the coenenchyma surrounds the corallites, 

 and encases them with a layer which has somewhat the appearance 

 of epitheca, and is of a sienna-brown colour, with a glossy fracture. 



Besides Stonesfield, I have also met with this species in a bed 

 quite at the top of the stone beds of the Hook-Norton railway- 

 cutting. The layers there exposed are Inferior Oolite ; but the one in 

 which these corals occur, and where they are unassociated with any 

 other species, is called the " rifted bed," and has been doubtfully 

 regarded as Great Oolite, overlying all the others. Most likely this 

 coralliferous layer corresponds with the lower part of the coral-bed 

 of Stonesfield. 



Becker and Milaschewitsch quote Cyathophora Bourgueti as 

 occuring with another species, C. marginestellata, in the corallian of 



