COKALS OF THE LIAS OF ENGLAND AND S. WALES. 187 



less favourable circumstances than the Fenuy-Compton examples* — 

 an opinion in which I myself at one time concurred. But the 

 acquisition of better-preserved specimens has led me to a different 

 conclusion. When the calice of these Pebworth corals is perfect it 

 resembles that of Montlivdltia patiila, but bears little resemblance 

 to that of Montlivaltia mucronata. Of course the turbinate form of 

 this coral does not identify it with M. mucronata any more than 

 with Montlivaltia Huperti or Montlivaltia sinemuriensis of DOrbigny, 

 both of which are turbinate species. At Pebworth, as at Welford 

 Hill, the corals occur on the top of the bed containing Ammonites 

 s&micostatus and A. JSauzeanus. I entertain no doubt that the 

 Pebworth corals are old examples of Montlivaltia patula, though 

 some of them in external form bear considerable resemblance to 

 Montlivaltia polymorpha. 



Thecosmilia socialis, n. s. (PL IX. figs. 5, 6.) 



This new and interesting species was taken by myself from a 

 quarry between the railway-cutting and the town of Bridgend, 

 Glamorganshire, in 1863. It was found in situ ; and in the same 

 stone bed were examples of Ammonites semicostatus and A.Sauzeanus. 

 I have seen but one specimen, and I describe it thus : — 



Corallum of a more or less globular form, but somewhat depressed, 

 and attached by the centre of its base. The upper half consists of 

 the calicular surface ; and the lower half is surrounded by a common 

 epitheca, which, near to the margins of the calices, curves inwards 

 and half surrounds them. It is thick, rugose, and concentrically 

 wrinkled. The calices are fifteen in number, and have a diameter 

 of about a quarter of an inch ; the central ones are rudely five- 

 sided, but the outer ones are nearly round. They are of medium 

 depth. The septa of the contiguous calices spring from the walls 

 exactly opposite to each other. They are straight, and retain their 

 thickness as they approach the centre. In the smaller calices there 

 are only three cycles ; but in the larger ones there are as many as 

 five. Those of the first reach the centre but do not unite ; those of 

 the second are nearly as long as those of the first ; those of the third 

 nearly as long as the second ; and those of the fourth and fifth 

 scarcely half the length of those of the third. The septa of the 

 first and second cycles have their margin armed with about six well- 

 marked sub-pointed vertical processes, those nearest the centre of 

 the calice being the most prominent. The dissepiments are not 

 very numerous, but are well developed and have a somewhat 

 tabular arrangement. 



Height of the corallum 1 inch. 



Greatest diameter 11 inch. 



Montlivaltia etjgosa, Wright, sp. 



Thecocyathus rugosus, Wright, Quart. Journ. Geol. Soc. vol. xvi. 

 I860, p. 411. (No. description given.) 



* Supp. Brit. Foss. Cor. pt. iv. No. 2, p. 58. 



o2 



