Protosalanx hyalocranius is widely distributed in China, especially in the coastal waters of the East Sea, Yellow Sea and Bohai Sea and in the middle and lower reaches of Jiang-Huai Plain.It can also be seen in Korea and Vietnam.Observation on the embryonic development of this fish was made in the winters of 1975, 1979 and 1982 separately.According to the experiments, greater part of extarnal egg-membrane consisted of rather fine threads starting from pole micropyle, the threads were subdivided and set so closely that no space existed between them until they reached a cenain distance from micropyle, which was also surrounded closely by fragments of threads arranged concentrically; numerous other fragments of threads scattered over remaining area.The fertilized eggs of this fish hatching took place in 33 days 18 hours 54 minute at the water temperature of 0.9-10.1℃.Newly hatched larva wab 5.74rnm in total length.The myomere number was 44+22=66.In 6 days, the mouth of old larva opend and the air bladder was abounded by gas.In 18 days, the yolk was almost consumed and the larva attained to 6.5mm in total lengths and the larva would die at the water temperature of 7.2℃.