chief Generic Types of Paheozoic Corals. 



71 



and intermediate areas of the corallnm is essentially and 

 fundamentally identical. They differ, howeverj in the struc- 

 ture of the great mass of endothecal tissue which occupies the 

 centre of the visceral chamber ; and these differences are shown 

 in the annexed sketches, where the structure of the central area 

 of these forms is represented. 



H ^^a»m^' 



Diagrams showing the structure of ClisiophrjUum and its allies. A. Dibu- 

 nophyllum ; 13, Aspidophyllum ; C, Rhodophyllum : D, type interme- 

 diate between Aspidophyllum and Rhodophyllum ; E, Clisiophyllum ; 

 F, Cyclophyllum ; 6, transition-form between Koninckophyllum and 

 the typical Clisiophylloids ; H, Carcino phyllim i (gen. nov.) ; I, tran- 

 sition-form, near G. Fig. E rep7esfeii"tS Across ^yflllUll biHJlmophyllum 

 coniseptum, Keys., of the natural size, in which the external and in- 

 termediate areas are introduced as well as the central. Figs. A, B, 

 C, D, and F are enlai'ged, and represent only the central area of the 

 coraUum ; to complete these figures, an external and intermediate 

 zone must be added, as in fig. V.. Figs. G, H, and I are likewise en- 

 larged, and represent the central area of the corallum, along with the 

 inner ends of the septa. The letter / indicates the position of the fossula. 



