18G ■ MADREPORAEIA. 



take place so near the wall as to appear part of the wall reticulum, the number of the septa 

 is thereby reduced to 12 ; this causes a superficial resemblance to the calicles of Pontes, but 

 traces of the typical formula may be seen in the very fact of this fusion. 



C. Dcep-Calicled Forms in which Traces of the Formula can still be seen. 



In forms with neat round calicles looking as if punctured into the smooth surface, a 

 conspicuous rosette of paliform plates appears to take the place of the septa ; this six-rayed 

 rosette is clearly a part of the typical septal formula, the rest of which may sometimes be 

 seen deep down in the calicle, e.g. G. Cliina Sea 4- This list need not be repeated, it is 

 given in Table IV., C. 



In other deep-calicled forms the formula, though quite lost in the calicles of the central 

 regions, may {a) reappear in the lateral calicles, or (b) may be seen in the fact that if the 

 calicle is looked at from above, or in section, the tertiaries often bend round towards the 

 secondaries. 



(a) G. North-West Australia 6. 



G. Philippines 4- 



G. Maldives 2. Obscured by parts of the fourth cycle. 



G. Red Sea 1. 



G. Red Sea 3. In traces. 



G. Red Sea 6. In very slight traces. 



(b) G. Tonga Islands 1. 



G. Vicenza 11. In section. 

 G. Genoa 4- 



We find, therefore, that there are about 38 forms in which the formula is known to be, 

 or can be assumed to be, typical, and close upon 60 forms in which it is altered and obscured, 

 though unmistakable traces of it can still be made out. These numbers would probably 

 be increased if the early " species " could be re-examined. 



