1. The authors give, in the present report, the descriptions of various abnormal mutant types of rice, which have been found by several Japanese breeders during these 30 years. 2. On the experimental results obtained by the authors during 1926-1935, the mode of inheritance of those mutant characters is discussed briefly. Special attentions were given to the linkage relation of the characters, as well as the F1 sterility of the intervarietal hybrid of Jap o nica and Indica.