ACTINOZOA. MADREPORARIA. 59 



Litharaea. Compound, massive. Calyces more or 

 less polygonal. Septa well developed, the faces spiny, the 

 upper edges dentate. Walls of the corallites reticulate. 

 Columella trabecular. In England, Bracklesham Beds ; 

 foreign, Eocene to Miocene. 



Favosites. Compound, massive, sometimes branched. 

 Corallites long and polygonal, the walls are in contact but 

 not fused, and they are perforated by pores arranged in 

 a row along each face, known as ' mural pores.' Tabulae 

 numerous, regular, generally extending quite across the 

 visceral chamber. Septa represented by rows of spines. 

 Bala to Carboniferous Limestone. 



Syringopora. Compound, fasciculate; corallites tu- 

 bular, for the most part not in contact. The visceral 

 chambers of the different corallites are placed in communi- 

 cation by means of horizontal connecting tubes. Tabula3 

 numerous, funnel-shaped. Septa feebly developed, gene- 

 rally represented by rows of spines. Budding basal. 

 Llandovery to Carboniferous Limestone. 



OBDEK. ALCYONAEIA. 



There are eight mesenteries and eight tentacles, the 

 latter being pinnate. The skeleton varies considerably, it 

 may consist of isolated calcareous spicules in the soft parts 

 (e.g. Alcyoniuni), of an internal axial rod formed of horny 

 material (e.g. Gorgonia) or of carbonate of lime (e.g. 

 Pennatula), or of both (e.g. Isis), or it may be external in 

 the form of calcareous tubes (e.g. Tubipora). 



Heliolites. Corallum compound, massive or branching, 

 not spicular, formed of tubes of two sizes, the larger 

 circular ones are known as autopores, between these come 

 the smaller polygonal siphonopores. Tabula? occur in both, 





