Nomenclature of parietal (A, B, D) and palatal (C) plicae and lamellae. A shows a “Gudeodiscus-type” plication with two lamellae B shows a usual Endothyrella lamellation D shows a “Chersaecia-type” lamellation with long lower plica and middle plica not connected to the apertural fold (in most species however, they are connected forming a continuous plica). Small arrows under the letters show the direction of the aperture (A shows dextral, B and D sinistral specimen). Large arrow next to C shows the direction of counting of palatal plicae (first above, last below). Abbreviations: af: apertural fold; al: anterior lamella; am: apertural margin (peristome); ip: intermediate plica; l: lamella; lp: lower plica; mp: main plica; pl: posterior lamella; pd: posterior denticles; pl: posterior lamella; up: upper plica. Note that there are upper and lower plicae on both (palatal and parietal) walls.