A description is given of the larval development ofPyura stolonifera.Ova were obtained by stripping the mature adult gonad and were artificially fertilized. Development is similar to that ofP. squamulosaandP. microcosmus.Successful development in specimens collected from False Bay takes place at 15°C to 25°C, but not at 10°C or 30°C. Rate of development increases with temperature.