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GENUS IV. EDWARDSIA (Quatrefages). 



Scolanthus (Gosse). 



Column long, slender, cylindrical, divided into 

 three distinct regions, of which the two terminal are 

 retractile within the central one. Anterior region 

 forming a short thick pillar (capitulum) of less diameter 

 than the central, and more delicate. Central region 

 (scapus) covered by a skin (epidermis) more or less 

 thick and opaque. Posterior region (physa) thin, 

 pellucid, inflatable like a bladder; imperforate (?). 



Dish sometimes flat, sometimes conical. 



Tentacles of one kind, few (less than thirty), mar- 

 ginal, arranged in one or two rows ; slender, mode- 

 rately long, pointed ; perfectly retractile. 



Mouth simple. No obvious gonidial development. 



ANALYSIS OF BRITISH SPECIES. 



Tentacles sixteen, transversely dashed with white ; 

 capitulum purple brown, with white markings ; lives 

 in sand callimorpha. 



Tentacles twenty-eight, pellucid crimson ; capitulum 



pellucid carneous ; lives in eroded rocks .... camea. 



