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GENUS III. CORYNACTIS (Allman). 
Base expanded, adherent. 
Column versatile, tall ; the margin forming a 
parapet, with no fosse. Surfaee smooth, without 
suckers or loopholes ; not invested with any separable 
epidermis. Substance fleshy or pulpy, pellucid. 
Dish flat, entire, circular. 
Tentacles in several rows, all of the same form ; 
each consisting of a conical stem and a globular head: 
perfectly retractile. 
Mouth simple, protrusile ; lip coarsely furrowed : 
stomach evertile. 
Only one British species exists, C. viridis. 
