The ultrastructure of the epithelial cell microvilli of the midgut of a decapod, Caridina denticulata , was studied. The microvilli have an axial bundle of filaments extend from the tip of the microvilli deeply into the interior cytoplasm of the epithelial cells. Basal globules were present at the base of the microvilli in the premolt stage animals. The length and arrangement of the microvilli change during the molting cycle.