10 



ANALYSIS OF THE GENERA. 



Tentacles moderately long, slender. 

 Disk perfectly retractile. 



Column destitute of suckers Aciinoloba. 



Column furnished with suckers Sagartia. ' 



Column clothed with a rough epidermis . . . Phellia. 

 Disk imperfectly retractile. 



Base annular ; parasitic on shells Adamtia. 



Base entire ; not parasitic Gregoria. 



Tentacles mere warts ; set in radiating bands [Not 

 British) Discosoma. 



