Lineus albocinctus (Nemertea, Heteronemertea, Lineidae), pilidium larva, length 390 to 550 µm, Helgoland 08.2011. 1:06 min. The taxon Heteronemertea in the taxon Nemertea or Nemertini develops characteristic planktonic pilidium larva (pilidum: form of roman helmet) with fore-lobe like a baseball-cap and hind lobe, at each side lateral lobes, all equipped with ciliary bands. The mouth is located between these lobes. An apical plate near the top bears a tuft of long stiff cilia. Video can be used for teaching.