Page:Quarterly Journal of the Geological Society of London, vol. 28.djvu/541

1872.] 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.

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