ACTIXOZOA. 



215 



often, it is wanting. In Cyathophyllmn and 

 certain allied forms there is a spurious columella 

 formed by the ** twisting together " of the inner 

 edges of the septa. 



In CystiphylluTn neither columella, septa, nor 

 tabulae can be distinguished. The whole interior 

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



Fifj. sS. 



Zapkeentis cylindeica. 

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



it were, broken up by the numerous lamin33 of a 

 sclerenchymatous deposit resembling the vesicular 

 substance of its epitheca and wall. 



Most Rugosa belong to the large group of 

 Cyathophyllidce. The remaining: families include 



but a few generic forms. 



Order EUGOSA. 



Family i. Staurid^. 



Corallum simple or composite. Septa 

 complete, united by lamellar dissepiments. 



P 4 



