Vol. 62.] LIMESTONE OF THE MENDIP AREA. 369 



reticulate structure of the peripheral area, which is discoutinuously 

 radiated by the septa. 



Cainpophyllmn aft'. Murchisoni, Edwards & Haime, Vaughan, Proc. 

 Bristol Nat. Soc. n. s. vol. x (1903) p. 116 & pi. i, fig. 5, differs 

 from our species only in the feebler definition of the septal break 

 and the wide, uniformly-thick zone of vesicles. This form, however, 

 was obtained l from the Dibunop7iyllum-Zone (Avon section). 



A Campophtllid. (PI. XXXI, fig. 3.) 



Horizontal section. — Outer wall strong. The wide peripheral 

 area, consisting of several rows of large, compressed vesicles, is not 

 radiated by the septa, and shows no septal projections; it passes 

 imperceptibly into the narrow, variable external area, which is 

 radiated by the septa and crowded with interseptal vesicles. The 

 inner boundary of the external area forms a somewhat feebly-defined 

 inner wall. 



The septa, 60 in number, are flexuous, thin, and all approximately 

 equal in length ; they stop short of the centre, leaving a central 

 area which is occupied only by a few curved tabular intersections. 

 The septa are festooned with tabular intersections in the medial 

 area. 



Intermediate septa practically absent ; represented only by very 

 few, minute projections from the inner wall. 



A well-marked septal break, formed by the shortening of one or 

 more septa, gives an appearance of bilateral symmetry to the 

 section. A fossula is indicated at this point, by the inward shift 

 of the tabular intersections, which form a series of arches. 



Vertical section. — The tabulae are broad plates, practically 

 flat in the centre, and bending downward within the septal zone. 

 A majority of them stretch completely across, but some are not so 

 continuous, and form very broad, flattened vesicles. 



The outermost zone consists of several vertical rows of ascending 

 vesicles. 



Remarks. — The affinities of this coral, which occurs in the 

 Upper JDibunophij Hum-Zone of the Mendip area, are somewhat 

 obscure, though its nearest allies are, certainly, the Gampophylla. 

 The form is, I think, of sufficient importance to be described and 

 figured; but the discussion of its affinities is best deferred, until the 

 collection of more material has thrown further light on the subject. 



Clisiophtllids. 

 Carcinophyllum. 

 Caecinophtllum mendipense, sp. nov. (PI. XXXI, fig. 4.) 



Form: conical. 



Horizontal section. — Central area circular and strongly- 

 bounded. Mesial plate, when present, short and thick. The 

 structure of the central area is essentially radial, the number of the 



1 Fide the late W. W. Stoddart. 



