127 



horizontal divisions extending from side to side of the general 

 cavity, instead of occupying only one or two of the locuU, 

 and closing the visceral chamber of the CoraUites at different 



heights. 



We divide the sub-order into four families— Millepoeid^, 



Favositid^, Seriatopoeid^, and Thecid^. 



The MiLLEPOEiD^ have the coraUum principaUy composed of 

 a very abundant ccenenchyma, distinct from the v^alls of the 

 CoralUtes, and of a tubular or ceUular structure; the tabula are 

 numerous and weU formed ; the septa not abundant. 



All the genera of this family are special to the Palaeozoic 

 epoch except those now living, and the genus Axopora, which 



is Eocene. 



The Favositid^ have the coraUum formed essentially by 

 lamellar waUs, with little or no ccenenchyma. The visceral 

 chambers are divided by numerous well-developed complete 

 tabulse. Nearly aU the genera of this family are special to 

 the Palaeozoic epoch— a single genus, Koninckia, is represented 

 in the Upper Chalk. Fociliojjora dates from the Miocene, and 

 lives in the present seas. 



The Seeiatoporid^ have the coraUum bushy or arborescent, 

 with an abundant and compact ccenenchyma, the visceral 

 chambers being fiUed up by the growth of the columeUa and 

 walls, and showing few traces of tabulae. 



This small family includes the living genus Seriatopora, one 

 Carboniferous, Bhabdopora, and two Devonian, Dendropora and 

 Tachypora. 



The THEOiDiE have the coraUum massive, with an abundant 

 compact spurious ccenenchyma, produced by the septa becoming 

 cemented lateraUy together. The tabula are numerous and weU 

 developed. It includes two genera, Thecia and Colvmnaria, 

 which are special to the Silurian period. 



4th S-wb-OrcZer. — ZoANTHARiA eugosa. — The coraUum is 

 simple or compound, and the septal system derived from fotir 

 primary elements, instead of six, as in the other sub-orders. 

 Sometimes this quadrate character is manifested by the existence 

 of four weU marked primary septa, or of an equal number of 



