Studies onDaphnia cephalata, relating to its longevity, instar duration, growth and fecundity have been made. Fifteen of the 22 individuals reared became primiparous at the fourth instar, the remaining at fifth. During growth, the total length, carapace length and carapace height increased by 2·95, 2·20 and 1·79 mm respectively and the growth curves for the 3 morphometric dimensions are of the same shape. About 200 eggs were produced during the life span of 52 days when the animals were reared at 27±2°C. The early embryogeny resembles other tropical daphnids but for differences in the developmental period in the brood chamber.