268 



ZOANTHARIA. 



Lophohelia likewise appear in the Tertiaries, the former in the 

 Eocene and the latter in the Miocene. Lastly, the widely dis- 

 tributed Recent genus Stylophora (fig. 144) appears as early as the 

 Eocene Tertiary. The corallum in this genus is readily recognised 

 by its granulated ccenenchyma, the presence of a styliform columella, 



Fig. 143. — Synhelia Sharpeana. Cretaceous. 



and the fact that there are six fully-developed septa, with an inter- 

 mediate cycle of six rudimentary septa. 



Family 3. Pocilloporidce. — The corallum in this family is compo- 

 site, with a dense ccenenchyma, the corallites having their visceral 

 chambers largely filled up inferiorly with solid stereoplasma (fig. 145, 

 c). The calices are oval, and are definitely oriented, their long axes 



corresponding with that 

 of the branches of the 

 corallum. The septa 

 are small, twelve in 

 number, with a distinct 

 bilateral arrangement. 

 The cavities of the pol- 

 ypes are placed in com- 

 munication (as in the 

 Alcyonarians) by a net- 

 work of canals, which 

 traverse the superficial 

 region of the colony. The mesenteries of the ventro-lateral pair 

 are, moreover, much longer than the others, and are the only ones 

 which carry mesenterial filaments, and which develop reproductive 

 organs. In Seriatopora, as shown by Moseley, these two mesen- 



Fig. 144. — a, The corallum of Stylophora subreticulata, 

 from the Miocene Tertiary of Austria, of the natural size ; 

 b, Surface of the same, enlarged. (After Zittel.) 



