SOME OBSERVATIONS ON SKIN OF OXYCHILUS SPP (FITZINGER), WITH PARTICULAR REFERENCE TO O HELVETICUS (BLUM) (MOLLUSCA, PULMONATA, ZONITIDAE)

A sub-epithelial collagenous layer and pits in the skin have been described in Oxychilus spp. The collagen is especially developed beneath the skin on the right side of the body in O. helveticus. It seems to arise from pore cells which previous authors have described in other molluscs. The pits in O. helveticus are lined by cells which together exhibit a gradation of electron densities. This probably represents an accumulation of secretory material and a macroapocrine secretory process has been observed. © 1969 Springer-Verlag.