pilidium
Pi*lid"i*um, n.; pl. Pildia. Etym: [NL., fr. Gr. (Zoöl.) Defn: The free-swimming, hat-shaped larva of certain nemertean worms. It has no resemblance to its parent, and the young worm develops in its interior.
Pi*lid"i*um, n.; pl. Pildia. Etym: [NL., fr. Gr. (Zoöl.) Defn: The free-swimming, hat-shaped larva of certain nemertean worms. It has no resemblance to its parent, and the young worm develops in its interior.