SUBCLASS I 



TETRACORALLA 



85 



I 



and Devonian. Grepidophyllwm Nich. Craspedophyllum Dybowski. Devonian. 

 Koninckophyllum Nich. Chonaxis E. and H. Carboniferous. ClisiophyUum 

 Dana. Silurian to Carboniferous. 



' OmphymaUai. (Fig. 116). Corallum simple, conical or turbinate; theca 



Fig. 113. 



(Jyathcq^hyllum heteropliyllmn B. and H. Middle De- 

 vonian ; Gerolstein, Bifel. A,y Transverse ; i>', Longi- 

 tudinal section (after Nicholson). 



Fig. 114. 



CmniwphyUum, com- 

 pressum Ludw. Car- 

 boniferous Limestone ; 

 Hausdorf, Silesia. a, 

 Longitudinal ; h, Trans- 

 verse section. 



Fig. 115. 



Dipliyphyllum con- 

 dniiiim Lonsd. Car- 

 boniferous Lime- 

 stone ; Kamensk, 

 Ural. 



with root-like processes. Septa numerous ; the four principal septa in shallow 

 fossulae. Surface marked with pinnately branching striae. Tabulae numerous. 

 Silurian. 



Chomphylhim E. and H. Silurian and Devonian. 



W 



Fig. 110. 



OmpUyma suhturhinata B. and H. Silurian limestone ; 

 Gotland, Sweden, a, Side view ; h, Calice from above. 



Fig. 117. 



Lithostrotioii 

 martini E. and H. 

 Lower Carbonifer- 

 ous ; Hausdorf, 

 Silesia. Sections 

 of individual 

 eorallite (after 

 Kunth). 



PtychophyUum E. and H. Simple and turbinate, or composite. Each 

 stock is composed of funnel-shaped, invaginated layers, representing calicinal 

 buds, the marginal lips of which are more or less reflected outwards. Septa 

 numerous and strongly twisted in the centre to form a pseudo-columella ; their 



