





ACTINOZOA. 



215 



often, it is 



wanting. 



In Cy athophyllum and 



certain allied forms there is a spurious columella 

 formed by the " twisting together " of the inner 

 eckes of the septa. 



In Cystiphyllum neither columella, septa, nor 

 tabulae can be distinguished. The whole interior 

 of the corallite, save its shallow calice, is here, as 



Fig. 38. 



Zaphrentis cylindrica. 

 (Part of a corallite, of the natural size.) 



it were, broken up by the numerous laminaB of a 

 sclerenchymatous deposit resembling the vesicular 

 substance of its epitheca and wall. 



Most Rugosa belong to the large group of 

 Gyathophyllidce. The remaining families include 

 but a few generic forms. 



1 



Order EUGOSA. 



Family 1. Staurid;e. 



Corallum simple 



or composite. 



Septa 



complete, united by lamellar dissepiments. 



p 4 



