Any of various small annelid worms belonging to the class Myzostomida, which have disc-like bodies with suckers and are commensals and ectoparasites of echinoderms, especially crinoids.
Myzostomids are placed by some authors in the class Polychaeta, as members of the family Myzostomidae.
Of, relating to, or designating a myzostomid.
Early 20th century; earliest use found in Encyclopaedia Britannica. From scientific Latin Myzostomida, class name from Myzostoma + -ida.