The two species of the genus Megalobrama are delicious food-fishes. Megalobrama terrninalis is more widly distributed; whereas the distribution of M. amblycephala is limited to lakes of the middle and lower Yangtze-kiang valley. As far as I am aware, the biology of these fishes is very incompletely known. During the year 1956 to 1957, a biological study of these fishes was undertaken in Lake Liang-Tze, Hupeh Province, and the results are dealt with here. The growth, the habitat, the age determination, the fluctuation of the metric and numeral characters, the reproduction and embryonic development, etc. form the principal items of this investigation.