FK03kl THE GKEAT OOLITE. 177 



primary ones swollen at their inner margins, somewhat as in 

 Scyphocoenia staminifera. 



Increase takes place by gemmation, quite at the base of the coral- 

 lites, probably from the basal coenenchyma, but not on any other 

 part of the corallnm. 



In its general form the only specimen I have seen bears consider- 

 able resemblance to the small and not much developed examples of 

 some species of Dendrophyllia, but only superficially, its affinities 

 being with the family Astreidse, while the absence of denticulations 

 on the margins of the septa indicates a place in the subfamily 

 Eusmilinse. 



Thamnoccenia oolitica, n. sp. (Plate Y. figs. 5-8.) 



The corallum has an irregular basal part, which is broadly attached 

 to a worn fragment of Platastrcea Conyheari, on which it spreads, 

 and which it partly covers. Prom this the corallites spring in a 

 more or less upward and outward direction. Gemmation taking 

 place at the base of the corallites gives to them somewhat the 

 appearance of having been produced in pairs. They are prominent 

 and cylindrical, but a little enlarged at their calicular ends. Both 

 the corallites and the spaces between them have long, straight, and 

 regular, but not prominent costse, which extend from the margins of 

 the calices downwards to the attached part of the corallum. 



The calices are circular and deep, and their margins are prominent 

 and thin. The septa are straight and project but little into the 

 calice. They are whoUy without denticulations, but those of the 

 first and second cycles have their ends much swollen, a good deal as 

 in the genus Scyphocoenia. Those of the first cycle are six in 

 number, and extend very nearly into the fossula, which is small, 

 circular, and distinct. The second cycle has septa which are very 

 nearly as long as those of the first, and the remaining cycle consists 

 of septa which are about three fourths the length of those of the 

 second cycle. These have very little prominence, and are without 

 the terminal swellings. 



The full height of the corallum is about 9 lines. The diameter 

 of the corallites is 2 lines. One specimen only has been met with ; 

 it was taken by me from the coralliferous layer on Combe Down, 

 and was in near proximity to a specimen of Barysmilia Etalloni. 



SCTPHOC(EinA ? 



I have obtained a coral from Combe Down, where it was associ- 

 ated with Barysmilia Etalloni and Thamnocoenia oolitica, which 

 possesses some of the characters of Scyphocoenia, but differs from it 

 in one very important particular. It bears considerable resemblance 

 to Scyphocoenia ecccelsa, in the form and arrangement of the coral- 

 lites, but the latter do not remain attached to each other excepting 

 quite low down. The septa appear to resemble those of Scyphocoenia 

 ■excelsa, and there are a few strongly developed tabulae, as in that 

 species. The specimen is, however, too much injured to permit of 

 detailed description. 



