114 PEOE. P. MAETIK DXJS"CAn's BEVISIOIf OE THE 



gonal and united. I'ive principal septa. No columella. Calices 

 from 1 to 2 millim. broad. 



Distribution. — Fossil. Cretaceous (JN"eocomian) : Europe. 



G-enus AcANTHOCffiNiA, d'Orhigny, Rev. et Mag. de Zool. 

 p. 175 (1850). 

 Colony massive. Calices circular, with free margins and a 

 styliform columella. Septa in three cycles, but there are only 

 five primaries. 



Distribution. — Fossil. Cretaceous (Neocomian) : Europe. 



VII. Alliance ELASMOCOENIOIDA. 



Agglomerate Astrseidse, increasing by gemmation between the calices. 

 Corallites united by a second wall, with or without exothecal coenen- 

 chyma. 



Genus Diploccenia, E. de From. 



Genus Diplocceniastr^a, D'Achiardi. 



Genus Diplothecastr^a, Duncan. 



Genus Koiloccenia, Duncan. 



Genus Anisoccenia, Reuss. 



Genus Heteroccenia, Ed. & H. 



Genus Elasmoccenia, Ed. & H. 



Genus Diploo(ENIA, F. de Fromentel, Notes a V etude des Polyp, 

 foss. p. 183 (1858-61) ; Descrip. des Folyp. foss. de Vetage 

 Neocom. p. 39, pi. v. figs. 7, 8, 9 (1857). 



Colony tall, or in a rounded mass. Corallites with two walls — 

 one projecting and hidden by the septa, but indicated by a circular 

 bourrelet ; the other united to the walls of the neighbouring 

 corallites separating the costse, and variable in its outUne. Co- 

 lumella styliform and strong. Septa entire, thick, and continuous 

 with the costge. Gremmation ? 



Distribution. — Fossil. Oolite and JSTeocomian : Europe. 



Genus Diplocceniaste^a, D'AcJiiardi, Goralli Giurassici delV 

 Italia Settent. (Pisa, 1880). 



Colony in thick laminae. Corallites immersed in the coenen- 

 chyma, which is compact. Calices circular, filling up below. 

 Columella small, spongy. Septa spinulose, straight, the larger 

 joiniug the columella, continuous with costse which occupy the 

 outer calicular spaces, and merge into those of neighbouring 

 calices. Gemmation peripheral. 



Distribution. — Fossil. European Oolite. 



