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GENUS IV. HORMATHIA (Gosse). 



Base adherent ; greatly expanded. 



Column pillar-like, much corrugated, surrounded 

 by a single horizontal row of warts. 



Disk slightly concave ; scarcely exceeding the 

 column. 



Tentacles moderately long and slender; perfectly 

 retractile. 



There is but a single known species, H. Margarita. 



