Collected specimen of Proseriata with structures of the rhabdocoel Phonorhynchopsis haegheni in the gut lumen. A complete animal body; B, C medial part of the animal body. Abbreviations: as4, accessory stylet type IV; b, brain; bu, bursa; gl, gut lumen; ph, pharynx; ps4, prostatic stylet type IV; s, statocyst; t, tale. as4, bu and ps4 correspond to the rhabdocoel and the other structures to the proseriate specimen.