Functional interrelations between aperture structures and soft organs in lower Geophila. 2. Achatinina

Three general functions of the apertural armature in lower Geophila (Pupill ina, Achatinina, and Oleacinina) were revealed based on studies of topograp hical relations between aperture structures and soft organs. Conchological and anatomical mechanisms of implementing these functions are considered. 1 . The gasket function is to prevent a shift of the cauliculus connecting th e visceral hump with cephalopodium in the aperture area. The aperture teeth cutting into the lung, as well as the developed mantle edge and clothing a pparatus, fulfill the function. 2. The shell management is achieved with th e columellar teeth (including the clothing apparatus), with elastic connect ive tissue partition of the visceral hump and by stay mechanisms, 3. Fixati on of female ducts is realized with parietal teeth, connective tissue parti tion, and connective tissue filaments attaching female ducts to the body wa ll. Hypotheses about the functional role of the apertural armature are anal yzed.