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GENUS L ZOANTHUS (Cuvier). 
Actinia (Ellis). 
Zoantha ) 
Zoanthus \ 
Mammilifera > (Lesueur). 
Corticijera ) 
Sidisia (J. E. Gray). 
Base permanently attached ; spreading over rocks, 
stones, or shells, in either a linear or incrusting 
manner. 
Coluimi pillar-like, higher than wide; margin cut 
into strongly marked teeth, which are united by a 
thin membrane. Surface smooth, excreting a mucus, 
in which occasionally grains of sand become imbedded, 
constituting an adventitious epidermis. 
Bisk slightly concave ; radii inconspicuous. 
Tentacles conical, pointed, similar in structure to 
those of AsTRiEACEA : wholly retractile. 
Mouth more or less protrusile, simple. 
ANALYSIS OF BRITISH SPECIES. 
Invested with sand ; extension various Couchii. 
Without sand — 
Polypes cylindrical, olive ; several abreast sulcaiut. 
Polypes obconic, pellucid white j in single file A Iden. 
