Holothuria

Linneaus, 1769

390 attributed species, 132 current

Mouth terminal, usually 20 tentacles. No anal teeth. Tentacle ampullae well developed; respiratory trees connected with alimentary canal by a rete mirabile. Cuvierian organs may be present. (Mortensen, 1927)

Tentacles 17-30, usually 20. Pedicels and papillae variously arranged on the ventral and dorsal sides respectively. Anal papillae variously developed or absent. Body wall quite variable. Body form showing a wide range, vermiform, cylindrical or with ventral side distinctly flattened and sole-like, dorsally arched. Size ranging from small to large, even massive, up to 450 (?600) mm. long. Calcareous ring more or less well developed, usually with radial plates two to three times as long as the interradial plates, the anterior margin of the ring rarely scalloped, the posterior margin undulating, except in the subgenus Theelothuria where the radial plates bifurcate posteriorly. Spicules quite diverse and variously developed, tables present, except in the subgenus Selenkothuria where tables are absent in five species out of seven and in the other two are said to be present only in very reduced form. (Rowe, 1969)