[Pteropoda] In Cymbuliidae, the calcareous shell is lost and replaced by a permanent cartilaginous, slipper-shaped structure: the pseudoconch (Cymbulia in oral view). Lalli and Gilmer (1989); also described as pseudoconch formations in Euthecosomata, but it seems not to be a permanent structure in this group.

Alternative form for Pseudoconch : slipper.