238 CEYLON PEARL OYSTER REPORT. 



Madrepora aspera, the apical polyps of Madrepora variabilis, Lophohelia, Seriato- 

 pora, Amphihelia, Stephanophyllia, Stephanaria, Sphenotrochus, Caryophyllia, 

 Trochocyatlms, Bathyactis. 



In Flabellum and Fungia there are both endosepta and exosepta, but the latter 

 eventually become endosepta on the formation of mesenterial pairs embracing them. 

 The list is incomplete, but it suffices to show that little reliance can be placed on the 

 mere presence or absence of exosepta. On the other hand, I believe that it is of 

 importance to discover in every coral whether the new endosepta are formed in the 

 forked peripheral extremities of the exosepta, or simply by the formation of a new 

 pair of mesenteries in connection with a radial upgrowth. 



