My zos to mid a

Group of Vermes, including only Myzos tom a, a genus of small disk-shaped hermaphrodites, parasitic upon Crinoids. They produce cysts on the integument that look like galls. They have four pairs of ventral suckers, five pairs of parapodia armed with hooks, etc., and a protrusible proboscis. Circulatory, respiratory, and excretory organs are absent. The intestine is branched, and the ova escape by the anus. Chandler's Encyclopedia