Gonads of V. pusilla at various growth stages were examined with standard histological methods. The first gonial cells appeared at the stage of 3.3 whorls: few and poorly developed gonad vesicles contained fine mitotically dividing cells and cells in meiotic prophase, with the first growing oocytes in the peripheral parts of the vesicles. At 4-whorl stage the oocytes entered vitellogenesis and increased in volume. In subadult individuals the oocyte volume and the gonad volume increased considerably; besides the advanced vitellogenic oocytes new oocytes appeared, the number of spermatids increased and the first spermatozoa were observed. The gonad of pre-reproductive adults contained numerous late-vitellogenic oocytes, young growing oocytes and many spermatozoa. In post-reproductive individuals there were no mature oocytes, spermatozoa were few, but the presence of young oocytes and mitotically dividing cells indicated resumption of gamete production.