CNIDARIA 



71 



C. Hexacorallia. 



Sub-Order 3. Antipatbaria (horn corals). — With 6 or 24 simple tentacles. Colonies 



with horny axial skeleton. Antipathcs (6 tentacles, only 2 developed septa), 



Gerardia (24 tentacles and septa). 

 Sub-order 4. Madreporaria (stone corals). 



— Mostly colonies, more rarely in- 

 dividuals mth strongly developed 



calcareous skeleton. 6ii simple ten- 

 tacles, and septa present in gi-eat 



numbers and variously arrranged. 



Madrepora, Astroides, Fungia, Astrcea, 



Mceandrina, Cladocora, Caryophyllia, 



Flabelhim. 

 Sub -Order 5. Actinaria (flesh corals). — 



Mostly individuals with 6n tentacles, 



and septa generally in considerable 



numbers and varied arrangement. 



Without skeleton. Cerianthus, Zoan- 



thus, Actinia, Anemonia, Adamsia, 



Edwardsia. 



Order 2. Scyphomedusae (Acraspeda). 



Mostly free-swimming individuals of bell- 

 or disc-shape, in which the mesodermal 

 supporting lamella is developed into 

 a large gelatinous mass. The ecto- 

 dermal oesophagus lies within a gastric 

 peduncle which hangs down from the 

 middle of the subumbrella. The 4 

 radial pouches of the Scyphula de- 

 generate in the higher forms. The 

 exumbrellar and subumbrellar walls of 

 the peripheral portion of the gastric 

 cavity grow together in such a way 

 that only a variously developed system 

 of radial gastro-canals remains. With 

 tufts of gastral filaments. A true velum 

 is wanting ; in its place, marginal 

 lobes, containing processes of the 

 gastro-canal system are present. 

 A. Medusce with deeply vaulted um- 

 brella. — The 4 radial gastric pouches and 

 the septa which separate them more or 

 less clearly retained. 



Sub-Order 1. Stauromedusse. — 4 septa 

 retained {Lmernaria) or reduced to 4 

 pillars {Tessera), 4 or 8 gonades in the subumbrellar wall of the 4 gastric 

 pouches, without sensory bodies (rhopalia). Lucernaria (attached, with 8 

 marginal lobes, each carrying a tuft of stinging batteries). Tessera (free, with- 

 out distinct marginal lobes, with 8 tentacles). 

 Sub-Order 2. Peromedusse. — The 4 septa reduced to 4 pillars, in consec[uence of 

 which the 4 gastric pouches are united into a circumferential sinus. With 4 



Fio. 



-Kophobelemnon Leuckartii. 



