17.6 E. p. TOMES ON MADKEPORAIIIA. 



calices, and others occupy flattened areas formed bj the union of the 

 corallites. They are circular and have very little prominence^ the 

 walls of the corallites continuing quite to the calicular margins. 



The septa are not exsert ; there are three cycles, and the septa of 

 the first, six in number, approach the fossula, which is rather deep ; 

 those of the second cycle are three fourths of the length of the 

 primary ones, and those of the third cycle are very short, almost 

 rudimentarye 



Several specimens have been taken from the coral-bed in the 

 Combe-Down quarry, all of which come well within the foregoing 

 description, though they vary somewhat in their relative height and 

 breadth. 



Prom EnalloTielia compressa and E. davata, with both of which 

 the present species agrees in the nnmber of primary septa, it never- 

 theless differs considerably : from the first, in its general habit of 

 growth ; and from the second, which, however, it more nearly re- 

 sembles, in not having exsert septa, in having the third cycle of septa 

 rudimentary, and in the absence of the enlarged inner margins of 

 the primary ones. There is no other species of the genus with 

 which it is likely to be confounded. 



Bathtccenia Slatteei, Tomes. 



Some ill-preserved examples of this coral have been taken from 

 the coral-bed on Combe Down by Mr. Slatter and myself. A single 

 worn specimen has also been obtained from the Great Oolite at 

 Caps Lodge, Burford, and is now in Mr. Hudleston's collection of 

 Great-Oolite corals from that and other localities in Oxfordshire. 



Great doubt is expressed by Prof. Duncan, in his " Eevision of 

 the Families and Genera of Corals," as to the distinctness of Bathy- 

 coenia from Styhsmilia, which genus, in habit of growth, it somewhat 

 resembles. A careful comparison of well-preserved specimens of 

 Tertiary Stylosmiliw, in my own cabinet, with Bathycoenia was made 

 by me when drawing up the generic definition of the latter, and the 

 absence of a true columella was clearly made out. The accuracy of 

 my diagnosis has been fully confirmed by the discovery of a 

 Bathyccenia in which the septa do not meet in the centre of the 

 visceral cavity, and in which therefore there is no columella*. 



Genus Thamkoccenia, n. g. 



The corallum consists of an irregularly formed and attached mass 

 of compact coenenchyma, from which corallites spring and present 

 the appearance of a straggling ramified cluster. 



The corallites have considerable prominence, the longest being 

 fully half the height of the corallum. The intercalicular portion, 

 as well as the free part of the corallites, is wholly without epitheca, 

 and has long and equal costse. 



The calices are deep and circular. The septa are entire and the 



* Since the above was written, I have detected tabulse in the calices of a 

 specimen of Bathyccenia Slatteri. 



