28 



BRITISH FOSSIL CORALS 



The septa are dentate, distinct, distant, unequal, stout, not exsert, and pass obliquely 

 downwards and inwards, so that they do not encroach much upon the calicular fossa. 

 There are eighteen in some and twenty-four in the largest calices. Three cycles appear 

 to be the normal number. There is no columella. 



The costae either reach on to the surface of the ccenenchyma or end abruptly at the 

 calicular margins, and they never become continuous with those of other calices. 



The stems are several inches in height, and are from ^ths to Ijths of an inch in 

 diameter. 



The calices rarely exceed ^th of an inch in diameter. 

 Locality. Brocastle. 



In the Collection of Charles Moore, Esq., F.G.S. 



The peculiar mineralization of the specimen prevents the structure of the central parts 

 of the stems being distinguished. 



There is a dendroid Astrocoenian in the Brocastle beds which has some resemblance 

 to this species, but the well-developed columella of the first distinguishes it at once. 



MM. Terquem and Piette have described a species Microsolena Fromenteli} whose 

 bush-like form and parallel constricted and irregular stems resemble Cyatlioco&nia 

 dendroidea, but the calices have a columella, and the costae are continuous ; nevertheless, 

 the " habit" of both species is very similar. 



2. Cyathoccenia incrustans, Duncan. PI. IV, figs. 1, 2. 



The corallum is very thin and encrusts portions of the shells of Bivalve Mollusca. 



The calices are unequal, circular or subpolygonal, rather close and very shallow. The 

 septa are few in number, are very small, and are marked with distinct and almost monili- 

 form processes. They are thickest at the margin of the calices. The larger septa usually 

 alternate with smaller, but, as a rule, the largest are the most numerous. 



The septa cannot be recognized as following a cyclical arrangement, and they vary 

 in number from fifteen to twenty. 



There is no columella. The ccenenchyma is scanty and is marked with large granules, 

 which are the representatives of costae. The gemmation occurs between the calices. 



Diameter of calices ^th to /^th of an inch. 



Locality. The Sutton Stone, encrusting an Ostrea. 



In the Collection of Charles Moore, Esq., F.G.S. 



The papillate septa and encrusting habit distinguish the species from C. dendroidea, 

 and C. costata. 



1 Op. cit., pi. xvii, figs. 11, 12. 



