FRENCH GONIOPOR.^. I37 



t 'alicles large, nearly 4 mm., concave. Walls tliick, and forming somewhat V)lunt ridges. 

 The angles thick, and tending to surge up with young buds appearing on them. The texture 

 of the walls is a very close reticulum of thin threads and minute pores, without beauty 

 of form. This close reticulum runs exit along the edges of the septa, broadened by tlie 

 synapticular proliferations characteristic of so many of these Paris Basin forms. It becomes 

 transformed, however, abovit half-way along the edges of the septa into a system of broad 

 flakes, which gradually sweep down into tlie floor of the calicle to form the columellar tangle, 

 which is composed of large, straggling, flattened flakes witli a few small perforations. The 

 septal formula appears to be typical, but confused by the extraordinary breadth of the 

 individual septa. 



The vertical section of this coral shows the thick horizontal flakes of the columella 

 thinning away on the lateral faces of the septa, which are not very perforate, but are covered 

 with small flattened projections, the synapticulse. 



This coral is much denser than either of the two foregoing, and had evidently a different 

 growth-form. A comparison of the figures of the calicles shows the differences between the 

 three. They are all variations upon the same method of protecting the retracted polyp against 

 sand or mud. These protections consist of the formation of («) flakes and (b) a filamentous 

 reticulum. In G. Paris Basin 5 the walls are flaky and the columella filamentous ; in 

 G. Paris Basin 6 the septa and columella are flaky, the flakes twisted about, and the walls 

 are an open elegant reticulum, while in this coral the walls are closely reticular, and the 

 columellar tangle is composed of horizontal flakes, the synapticul^e changing from filaments 

 to flakes. 



I am inclined to tliink that while the two former built up light masses, this coral was 

 tougher and thinner, and possibly encrusting. 



a. Geo. Dept. I!. 4219. 



1?A. Goniopora Paris Basin ^4)8. (PI. X. fig. 8.) 

 [Parnes ; Middle Eocene ; British Museum.] 



Description. — Corallum thin, encrusting, 4-5 mm. thick; surface almost flat, or only 

 slightly convex ; thick, white, wrinkled epitheca. 



Calicles 3-3 '5 mm. across, sub-polygonal, shallow concave depressions. Walls uniform, 

 blunt ridges about • 5 mm. thick. The septa uniformly thickened by a dense, finely granidar 

 proliferation of the synapticulfe, which runs up to the wall-ridge here and there, changing it 

 into a close reticulum with minute pores. Towards the centre of the calicle the synapticular 

 proliferations change into flakes, whicli form the columellar tangle. The surface of this is 

 finely roughened, and is perforated by a few minute pores. 



The vertical section shows an exquisitely delicate, nearly uniform reticulum, in which, 

 however, the closely arranged horizontal wavy flakes are the chief constituents, there being no 

 very distinct vertical trabecular elements. 



This coral is evidently closely allied to the last. There are three specimens, a portion of 

 a thin encrusting stock, ami two minute young colonies, differing from the stock in that the 



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