196 



FOSSIL ACTINOZOA. 



The Perforate Corals are divided into the following three 

 families if we omit the Favositidce, the true place of which 

 is still uncertain : 



1. Eupsammidce. In this family the corallum may be 

 simple or compound, the wall being always perforated and 

 granular, while the septa, though comparatively well devel- 

 oped and lamellar, are generally also perforated. There is 

 a spongy columella, and the interseptal loculi are open, or 

 crossed by but few dissepiments. 



Fig 82. Endopachys Madurii, viewed in profile and from above. Eocene Tertiary. 



The most ancient type of the Eupsammidce is the Upper 

 Silurian Calostylis, but with this exception the earliest 

 known representatives of this family occur in the Cre- 

 taceous (StepJianophyllia\ and there is a considerable ex- 

 pansion of the group in the Eocene Tertiary. In Eupsam- 

 mia itself, the corallum is simple, free, and turbinate 

 in shape; and Endopachys (fig. 82) is essentially the same, 

 except that it is much compressed, and its keeled base is 

 continued into two wing-like expansions. Balanophyllia, 

 ranging from the Eocene to the present day, is also simple, 

 but the corallum is fixed ; while the Cretaceous and Tertiary 

 StephanopJiyllia is free, simple, and discoid, with an open 

 circular calyx. Dendrophyllia, again, a well-known recent 

 type, is composite, the corallum increasing by lateral gem- 

 mation, so as to assume a dendroid or shrub-like form. It 

 begins in the Eocene Tertiary. 



2. Madreporidce. The members of this family are dis- 

 tinguished by possessing a composite corallum, increasing 

 by gemmation, the various corallites being united by an 

 abundant and spongy ccenenchyma. The walls of the coral- 

 lites are not distinct from the ccenenchyma, and are porous, 



