ANTHOZOA. ZOANTHARIA 



89 



fluent. Theca thin or indistinct. No columella. Tabulae and 

 dissepiments well developed. Devonian and Carboniferous. Ex. 

 P. hennahi and P. pengellyi, Devonian ; P. radiata, Carboniferous. 



Lithostrotion. (fig. 31.) Compound, either massive and 

 with prismatic corallites, or formed of separated, nearly parallel, 

 cylindrical corallites. Septa well developed, alternately long and 

 short. Columella rod-like, laterally compressed. Peripheral zone of 

 dissepiments narrow. Tabulae wide, occupying the centre of the 

 visceral chamber. Fossula often distinct. Carboniferous. Ex. L. 

 basaltiforme. 



Omphyma. Simple, turbinate or conical. Septa numerous, 

 alternately long and short, but extending only a short distance into 

 the visceral chamber, the central part being occupied by tabulae. 

 Four shallow fossulae are present. No columella. Peripheral zone 

 of dissepiments relatively narrow. The theca gives off root-like 

 processes. Bala to Lower Ludlow. Ex. 0. subturbinata, Wenlock 

 Limestone. 



a 



Fig. 32. Fig. 33. 



Fig. 32. Cli stop hy Hum bipartitum, Carboniferous Limestone. Horizontal 

 section showing the large central 'pseudo-colurnella.' Natural size. 



Fig. 33. Cyclophyllum fungites, Carboniferous Limestone. Horizontal 

 section, a, cardinal fossula. x 1^. 



Clisiophyllum. (fig. 32.) Simple, turbinate or subcylindrical. 

 Septa numerous, alternately long and short ; a well-marked cardinal 

 fossula. In the centre of the visceral chamber is a large ' pseudo- 



