The reproductive cycles of male and female Anadara granosa and Anadara antiquata which have been
studied and compared by histological techniques showed great anatomical similarity. Gametogenesis isvassociated with a system of follicle cells which break down as the gametes approach maturity. Thevarrangement of follicle cells is characteristics of the sex. In the female, gametogonia are peripheral tovthe follicle cells, whilst in the male they are interstitial. The process of spermatogenesis parallel thevclassical vertebrate pattern, i.e. successive layers of spermatogenic cells (spermatogonia, primary andvsecondary spermatocytes, spermatids, and spermatozoa) occurring more or less regularly in successionvtoward the centre of the follicle. The diameter of the maximum size oocytes is 75µm for A. granosa and 65µm for A. antiquata. Spawning in both A. granosa and A. antiquata is progressing gradually throughout the year as indicated by the availability of various stages of oogonia and spermatogonia; forvwhich the highest number of oogonia were those of 25-40µm diameter. The histological study indicatedvthat both species are iteroparous with planktotrophic type of development, yet performing a shortvperiod of pelagic life (ca 1 month).