English: Diversity of Myzostomida and their relationships with echinoderm hosts. (A)Myzostoma capitocutis (Myzostomatidae), free-living. (B)Myzostoma eeckhauti nomen nudum (Summers & Rouse, in press.) (Myzostomatidae), free-living. (C)Pulvinomyzostomum inaki nomen nudum (Summers & Rouse, in press.) (Pulvinomyzostomatidae), found in or near mouth. (D)Mesomyzostoma sp. (Myzostomatidae, previously Mesomyzostomatidae), resides within the host’s coelom.(E)Asteromyzostomum grygieri nomen nudum (Summers & Rouse, in press.) (Asteromyzostomatidae), recovered externally with mouth pierced through body wall. (F)Notopharyngoides aruensis (Myzostomatidae), found in mouth. (G)Protomyzostomum roseus nomen nudum (Summers & Rouse, in press.) (Protomyzostomatidae), found within the host’s coelom. (H)Myzostoma divisor (Myzostomatidae), free-living.(I)Notopharyngoides platypus (Myzostomatidae), resides permanently in cysts. (J)Contramyzostoma bialatum (Myzostomatidae, previously Endomyzostomatidae), resides permanently in cysts. (K)Myzostoma longitergum (Myzostomatidae), free-living. (L). Endomyzostoma neridae nomen nudum (Summers & Rouse, in press.) (Endomyzostomatidae), lives within galls. A, D, I, K—Raja Ampat, Indonesia. B, J—Madang Habor, Papua New Guinea. C—Costa Rica. E, H—Antarctica. F—Lizard Island, Australia. G—Monterey, California. L—Dili, East Timor. Scale bars 1 mm (A, D-G, I-L); 0.5 mm (H); 0.2 mm (B, C).