110 PEoi'. P. MARTIN Duncan's eetision of the 



and numerous or few. Occasionally some primaries are larger 

 than others. Cycles hexameral, or octameral, or decameral. The 

 walls are thick. Costse well developed. The endothecal dissepi- 

 ments are simple or subvesicular. Gremmation is from the wall 

 outside of the calice and from the intercalicular space. 



Distribution. — Fossil. Trias : Europe. Oolite : England and 

 Europe. Cretaceous : Europe. 



Eelioccenia, Etallon (genus), appears to differ from Stylina in 

 having costse which do not extend far from the calicular margins. 

 The columella is sometimes a little compressed. These are hardly 

 generic distinctions, and I propose to consider Heliocoenia as a 

 subgenus. 



Grenus Psammoc(enia, Milne-Fdwards Sf Jules Saime, Hist. 

 Nat. des Gorall. vol. ii. p. 285 (1857). 



Colony massive. Corallites separated by exotheca. Calices 

 unequally close .and irregularly projecting, small. Columella 

 styliform. Septa divided into six simple systems and there are 

 six pali. Intercalicular area granular, and hardly striated with 

 costse. 



Distribution. — Fossil. Ligsdorf (Haut E-hin), Europe. 



Tribe II. 



Genus Columnastr^a, Milne-Edwards 8f Jules Saime, Hist. 

 Nat. des Gorall. vol. ii. p. 262 (1857). Illustrated by Eeuss, 

 Denkschr. der "Wien. Akad. der Wiss. t. vii. pi. 14. figs. 1 & 2 

 (1854), and Duncan, "West-Indian Corals," Proc. Greol. 

 Soc, Dec. 1867, pi. v. figs. 1 a & 1 6 (by error the word " sto- 

 loniform" was printed for "styliform," p. 18). 



Colony massive, convex, lobed, or subdendroid. Corallites 

 united by costse. The calices are moderately deep, circular, and 

 projecting, and have their margins free. The columella is styli- 

 form and not much developed. The septa are thin, arched where 

 free, denticulate. There are pali which form a single crown. 

 The costse are well developed. The gemmation occurs from the 

 intercorallite tissue. 



Distribution. — Fossil. Cretaceous : Europe. Eocene : West 

 Indies. Pliocene: Europe. 



E. Pratz has shown that the septa of the species of this genus 

 are not entire at the free edge. 



