English: From source: Protaster? sp. (OUMNH PAL-C.36516). A–C, E–F, H–I, K, virtual reconstructions as stereo-pairs. A, oral; B, aboral; C, lateral view. D, section through disc showing body cavity. E, transparent view to highlight tube feet and internal soft tissues. F, sharply folded arm in oral view. G, oral view with arms outlined. H, sharply folded arm (and adjacent arm) in lateral view. I, ‘posterior’ arm in oral view showing tube feet; and J, their points of origin (podial basins: red circles) displaying the offset of ambulacral plates. K, lateral view showing extension of tube feet and some groove spines. Abbreviations: ad, adambulacral plate; ag, ambulacral groove; amb, ambulacral plate; ao, aboral surface; d, depressed part of aboral surface with ragged disc margins; m, mouth; mp, mouth plates; o, oral surface; pb, podial basin; per, perforations; ps, perradial suture; s1–s3, sac-like internal structures 1–3; sp, groove spine (red); tf, tube foot (purple). Scale bars represent 1 mm.