ABSTRACT
This chapter reports the results of a complete cytochemical study using Gomori’s reaction, both in the course of the vitellogenesis and during early development of the egg of Asterina gibbosa. During oogenesis, at the end of the previtellogenic stage, dictyosomes secrete acid phosphatase and we observe true lysosomes which participate in yolk formation by fusion with endoplasmic reticulum cisternae. So, when vitellogenesis begins, all yolk globules contain this enzyme. However, the intensity of histochemical reaction decreases with the onset of oocyte maturity. After spawning, acid phosphatase is not detectable again until the blastula has been formed. Activity increases during the formation of the lecitotrophic larva, at the yolk globules level. No acid phosphatase is found in the Golgi apparatus of embryonic cells, so it is presumed that the enzyme previously observed in the vitellogenic oocyte, inactivated in the late oocyte and during the early cleavage stages, reappears when yolk consumption occurs, i.e after blastulation.
