30 



BRITISH FOSSIL CORALS 



2. Elysastr.ea Moorei, Duncan. PI. VI, figs. 10 — 15. 



The corallura is massive, and the upper surface is very ii-regular. 



The coralHtes are joined by their walls in many places, but are free in others, Ijoth 

 superiorly and lower down in the corallum. 



The corallites vary greatly in size, and the smallest are usually joined by their 

 walls, and are more or less angular in outline. The largest corallites are circular in 

 outline. 



The calices are irregular in their depth, and are either circular or polygonal. They 

 are close, even when not adherent. 



The septa are alternately large and small, are faintly dentate, and are very variable in 

 number. There are forty-eight septa in the largest calices. 



The costae are continuous with the septa in the separate corallites, but do not exist 

 when the walls are united. 



The columella is deficient. 



The endotheca is very abundant. 



The diameter of the calices is from fgths — /oths inch. 



Locality. The Sutton Stone, and at Brocastle. 



In the Collection of Charles Moore, Esq., F.G.S., Bath. 



The genus Eli/sastraa is very remarkable ; it has affinities with Isastraa and with 

 the very close bush-shaped Thecosmilia . The Imsh-shaped Thecosmilia are noticed to 

 become united by their walls in some specimens, and the walls of Sejjfastrace and 

 PrioastrcBiB are occasionally not united inferiorly. 



The species Elysastraa Moorei has its corallites more distinctly separate than the 

 St. Cassian form, which is, however, clearly represented in the Sutton Stone. 



The appearance of septa near the centre of the calice is very characteristic of 

 the genus. 



Genus — Isastr^a. 



1. IsASTR^A SiNEMURiENSis, E. de Fromentel} PI. VII, figs. 1 — 9. 

 The calices are polygonal, and tolerably deep. 



The septa are very numerous, spined, close, and unite occasionally by their inner 

 ' Martin, ' Pal. Strat. de I'lnfra-Lias dii dep. de la Cote d'Oi,' 1860, pi. vii, fig?. Hi, 17. 



