CLASSIFICATORY POSITION OP SOME MADEEPOKAETA. 115 



the whole of the species are replaced in their original generic environ- 

 ment {ante, p. 101). 



Genus CrATHOccENiA, Dune. 



This genus is criticized by Mr. Tomes {pp. cit. p. 372), and is 

 said to be the same as PJtylloccenia, Laube. But an examination of 

 Phyllocoenia, Laube, shows it not to be the same as Pliylloccenia, 

 Ed. & H., which had precedence in time, and to which Laube reaUy 

 intended to refer his form. 



Cyatliocoenia differs from the form described by Laube under the 

 generic title of Phyllocoenia, which it had not properly, for in the 

 St.-Cassian form there is a remarkable development of the exotheca, 

 which forms a double wall to the coraUites. This takes the genus 

 into the neighbourhood of Diplocoenia, E. de From., and far away 

 from Cyathoccenia. The form described by Laube has been the 

 subject of comment in the " Revision of the Genera of Madre- 

 poraria" (Linnean Soc. 1884), and it is now included as a new 

 genus, Koilocoenia. CyatJiocoenia^ nobis, therefore remains as a genus 

 of the Infra-Lias. 



" Cyathoccenia decipiexs, Laube, sp." (R. F. Tomes, op. cit. p. 372). 



This is the name given to a single specimen. The figure shows 

 that the specimen may belong to a species of the genus CyatJiocoenia, 

 in which Mr. Tomes has placed it ; but it is not of the same 

 species or of the same genus as the form described under Pliyllo- 

 ccenia clecipiens by Laube. It is very curious that the peculiar 

 structure of the double wall of the St.-Cassian form did not strike 

 Mr. Tomes, for it is well drawn by Laube, and its existence separates 

 the form from Phyllocoenia, auct., and Cyathoccenia. C. decipiens, 

 Laube, s^.^= Phyllocoenia decipiens, Laube, is therefore not a member 

 of the Infra- Liassic fauna at present, and the scanty details of the 

 figure (E. F. Tomes, op. cit. plate xix. fig. 3) indicate that the speci- 

 men is a very indifferent one. 



Genus Thecosmilia, Ed. & H. 



The interesting peculiarities of the species of this genus, which 

 are found in the Sutton-Stone, Brocastle, and other Infra-Lias 

 deposits, and their comparison with the allied species from St. Cas- 

 sian, were fully considered in my Monograph published by the Palae- 

 ontographical Society* and in a paper read before this Society f. 



There are some exceptions taken to my work. In the first place 

 Mr. Tomes asserts that Thecosmilia Martini and T. Michelini (both 

 found in the Hettangian of Europe) are absent. But both of these 

 well-marked Infra-Lias species were figured and described by me 

 in the Monograph ; and they came from the late Mr. C. Moore's 

 collection, and are now in the Museum at Bath. They are important, 

 for their presence diminishes the value of Mr. Tomes's data, which 

 would give a Triassic age to the Sutton Stone and associated deposits. 



* Brit. Foss. Corals, 2ncl ser. pt. iv. 1SG7, p. 11. 

 t Quart. Journ. Geol. Soc. vol. xxiii. p. 12. 



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