544 R. F. Tomes — Some Cretaceous Madreporaria. 



There are six systems, and four complete cycles, and a fifth which is 

 incomplete. 



Those of the first cycle are long, and approach very near to the 

 axial space, and their lateral spines, which are scarcely observable 

 near the wall, gradually increase in size and prominence towards 

 their inner margin, where they are much pronounced and have a 

 rugged nodular growth. The septa forming the second cycle are 

 three-fourths the length of those of the first, and are similarly 

 furnished with rugged and warty processes (spines ?) at their inner 

 margins. The third cycle has septa which are three-fourths the 

 length of those of the second, and which have also similar excrescences 

 at their inner margin, and the fourth is formed by septa which are 

 scarcely half the length of the third, while those of the fifth cycle 

 ai'e very short, simple, and irregular, and even absent in some of the 

 systems. The spinous processes of the septa, which are confined to 

 the first three cycles, have sufficient prominence and irregularity of 

 growth to mix and form a loose mass, which occupies the whole of 

 the middle part of the calice. There is considerable irregularity in 

 the degree of development of this in different examples, and in some 

 of them it fills up the calice so much that the cycles are difficult 

 to trace. I have examined fifteen specimens of this species from the 

 Gault of Folkestone, not one of which has the margins of the septa 

 uninjured, while the calice of most of them is much, damaged by 

 pyrites. A single specimen from the Speeton clay of Yorkshire has 

 also come under my observation. It is a small one, and the oblique 

 foot and the peculiar septal processes are not greatly developed. 



The height of the largest specimen I have seen is a little more 

 than half an inch, and the diameter of the calice three lines. 



It is with considerable doubt that I place this curious species in 

 tbe genus Smilotrochus. 



Cyclocyathus Fittoni, var.? 



Micrahacia Fittoni, Duncan, Suppl. Brit. Foss. Cor. pt. ii. p. 37, pi. xiv. figs. 6- 9, 



1870. 



More than twenty years ago I received from the late Dr. S. P. 

 Woodward a small collection of corals from the Gault of Folkestone, 

 in which was a specimen which, though labelled by him Cyclocya- 

 thus Fittoni, appeared to differ from all the others which were 

 similarly named, and from the same locality. It corresponds in 

 every particular with Micrahacia Fittoni, Duncan, and, like the 

 figured specimen, had the whole of the central region obscured 

 by stony matter. Fortunately the usually troublesome and destruc- 

 tive pyrites was absent, and black and apparently phosphatic lime, 

 though hard, gave way to and was readily scooped out by a sharp 

 steel instrument, and a deep calice revealed. In this is a papillous 

 columella and a ring of pali. These are seen in section, and being 

 of a pure white colour, are very clearly defined by the surrounding 

 black substance with which the loculi are filled. Compared with 

 the same parts in Cyclocyathus Fittoni, they correspond very closely, 

 and all further question about the generic affinities of the species 



