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ANALYSIS OF THE GENERA. 



Tentacles of one kind, marginal. 

 Column thick, pear-shaped. 



Mouth with a papillate gonidial tube Peachia. 



Mouth simple Ilyanthus. 



Column slender, long, worni-sliaped. 



Invested with an epidermis Edwardsia. 



Without an epidermis Halcamjxi. 



Tentacles of two kinds, marginal and gular. 



Naked; freely swimming Arachnactis. 



Dwelling in a membranous tube ; sedentary. 



Column inferiorly perforate Ccrianthus. 



Column inferiorly imperforate {Not British) . . Saccanthus. 



