﻿Vol. 66.~] LIMESTONE SOUTH OF THE CKA.VEN FAULT. 571 



remarkably uniform septa, but it is noteworthy that a lower section 

 of the same coral showed less regular septa. In this respect it is 

 again somewhat like Caninia cornucopia?, as described by Mr. B,. G. 

 Carruthers. Minor septa are rarely seen ; only in the latest 

 growth-stages have I been able to detect them, and then they are 

 usually small. 



The tabuhe generally extend from wall to wall, occasionally, 

 however, coalescing one with the other. They are fairly flat in 

 the middle part, dipping sharply at each end. Occasional large 

 dissepiments rise irregularly from the upper surfaces. These dis- 

 sepiments and the tabulae are intersected by the transverse sections, 

 and originate the irregular lines which are so marked a feature 

 in sections of the Amplexoid stages of the coral. There does not 

 seem to be, even in the latest stages of growth, any tendency to 

 the development of an external zone of dissepiments. 



The reason why I have provisionally included this remarkable 

 and variable coral in the genus Zaphrentis will appear from the 

 descriptions given and from an inspection of the figures. It may 

 be well now to summarize those reasons. 



I have excluded it from Caninia, because there is no external 

 zone of dissepiments in any specimens that I have examined ; 

 also, in a minor degree, because of the presence of three (or even 

 four) fossulae in certain specimens and in certain stages of growth. 

 In the earlier stages the cardinal fossula is completely enveloped 

 by two or more septa which wrap round its inner end. The 

 coral has, however, affinities with Caninia in its general septal 

 development. 



I have excluded it from Amplexus, because of the great length 

 of its septa in the early stages, and 'also because of the well- 

 developed fossula or fossulae. There are, too, more dissepiments 

 than are common in most species of Amplexus. It has affinities 

 with Amplexus in its short septa of the later stages and in its 

 tabulae ; many of the latter extend almost horizontally from wall 

 to wall, and they are sometimes a considerable distance apart 

 from each other. 



Prom Calophyllum it is separated by the very rudimentary 

 development of its minor septa. 



The reasons for its inclusion in Zaphrentis follow from the fore- 

 going statement : its well-marked cardinal fossula in the earlier 

 stages ; the counter and alar fossulae which are often seen ; the way in 

 which the septa enclose the cardinal fossula ; the extension of the 

 septa to the middle of the coral in the earlier stages ; and, finally, 

 the scattered dissepiments, are all in keeping with its inclusion in 

 Zaphrentis. 



The specific name which I have provisionally attached to it recalls 

 its pronounced Amplexoid characters. 



I have found one specimen at Crag Laithe which seems to be the 

 same, and one at Otterburn ; otherwise I have not met with it 



Q. J. G. S. No. 264. 2 b 



