1872.] DUNCAN TEOCHOCYATHUS ANGLICUS. 447 



I. On Tkochoctathus angucfs, a new species of Madeepokakia 

 from the Eed Crag. By P. Martin Duncan, M.B., r.E.S.,V.P.G.S., 

 (fee, Professor of Geology in King's College, London. 



[Plate XXVIII.] 



Contents. 

 I. Locality and description of the species. 



II. Remarks on the aiflnities of the species. 



III. Considerations respecting the coral fauna of the English Pliocene deposits. 



I. The coral about to be described was found in the Eed Crag 

 within the grounds of Great Bealiugs Eectory, Suffolk*. There is 

 only one specimen ; but it is so well preserved, and its anatomical 

 details are so perfect, that there is no difficulty in giving the form a 

 generic and specific appellation. 



Trochocyathus anglicus. pi. XXVIII. figs. 1-4. 



The coral is subhemisjjherical in shape, and has a smaU flattened 

 base, upon which there are the marks resulting from the disruption of 

 a former adhesion (fig. 4). The outside of the coral, from the cicatrix 

 at the base to the calicular margin, is covered with a smooth, opaque, 

 and plain epitheca. The epitheca hides the costae, and is faintly orna- 

 mented superiorly with an indistinct " Vandyke " pattern. The calice 

 (figs. 1,2) is nearly circular in its outline, is slightly inverted at the 

 margin (which is broad), and is shallow. The columella is formed by 

 the junction of the pali and by a small amount of proper tissue ; it is 

 small but prominent, and rises to a higher level than the septa at 

 their junction with the pali. The septa are long, unequal, separate, 

 and non-exsert ; there are six systems of them ; and there are the 

 members of four cycles in each system. The primary septa are 

 slightly larger than the secondary ; and both dip down from the in- 

 verted margin of the calice into the fossa and come into contact with 

 pali. The septa of the third cycle are smaller than those of the 

 second, and are slightly wavy in their course. The septa of the 

 fourth and fifth orders of the fourth cycle are smaller than the ter- 

 tiary, to which they are united close to the junction of these septa 

 with their pali. The septa are ornamented with large, acutely 

 pointed, granular and papular elevations on their sides. This orna- 

 mentation is nearly confined to the columellar end of the large 

 septa ; but the septa of the third and fourth orders are granulated 

 throughout their whole length. In their breadth the costse are 

 larger than the septa to which they correspond ; they are moderately 

 unequal, close, and triangular in outline ; they are only visible at 

 the calicular margin. The wall is seen in the form of a series of 

 processes which pass between the adjacent costee close to their junc- 

 tion with their respective septa. The pali of the third cycle of septa 

 are the largest and most external ; those of the secondary septa are 

 distinct, bi;t those of the primary are very small ; all are granular. 

 Some of the granular-looking papillae of the higher orders of septa 

 occasionally unite like synapticulae. 



Width of the calicular end y^^ inch ; height of the corallum -f^ inch. 



* Mr. C. J. A. Meyer, F.G.S., procured the specimen and obtained the details 

 of its discoTery. 



