II 



C XI D ARIA 



71 



C. Hexacorallia. 



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

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

 Gcrardia (24 tentacles and septa). 



Sub-order 4. Madreporaria (stone corals). 

 Mostly colonies, more rarely in- 

 dividuals with strongly developed 

 calcareous skeleton. 6?i simple ten- 

 tacles, and septa present in great 

 numbers and variously arrranged. 

 Mudrepora, Astroidcs, Fungia, Astrcea, 

 Mtmndriiut, Cladocora, CaryophylUa, 

 Flabellum. 



Sub -Order 5. Actinaria (flesh corals). 

 Mostly individuals with &n tentacles, 

 and septa generally in considerable 

 numbers and varied arrangement. 

 Without skeleton. Cerianthus, Zoan- 

 thus, Actinia, Anemonia, Adamsia, 

 Edwardsia. 



Order 2. Scyphomedusse (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 cesophagus lies within a gastric 

 peduncle which hangs down from the 

 middle of the subumbrella. The 4 

 radial pouches of the Scypliula 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. AVith 



tufts of gastral filaments. A true velum 



is wanting ; in its place, marginal 



lobes, containing processes of the 



gastro-canal system are present. 

 A. Mcdusce with deeply vaulted um- 

 brella. The 4 radial gastric pouches and 

 the septa which separate them more or 

 less clearly regained. 

 Sub-Order 1. Stauromedusse. 4 septa 



retained (Luccrnarict) 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 S 



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 consequence of 



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



' 



FIG. 03. Kopho'oelemnon Leuckartii. 



