Fine structure of principal and basal cells of the cauda epididymidis of the South American opossum (Didelphis azarae).

The aim of the study was to investigate cytological characteristics of principal and basal cells, at the ultrastructural level, in the cauda epididymidis of the opossum. Adult sexually mature opossums were used. Signs of pinocytosis and absorption and secretion were seen in both cells. These functions and the fine structure of the principal and basal cells of this marsupial are discussed comparatively with the fine structure of these cells in the epididymidis of eutherian mammals.