Abstract
1. In this article, the results of limnological studies, with special reference to the bottom fauna of the Yosino River, carried out on July 20, 1935 and August 3-6, 1936 are reported.
2. The observations of the fresh water 'area are shown in tables 1, 2 and figs. 1, 2.
3. The brackish water area was studied only at tidal zone (figs. 3. 4 and tables 3, 4). The dominant species of animals are Scopimera globosa and Corbicula japonica at station II, and an isopod at station I. Nereis japonica and Assiminea japonica were found only station IV. According to the occurrence of these species in the brackish water area, the type of the bottom appears to be the limiting factor to their distribution, a fact which has been noticed by several investigators (TAKAHASHI 1934, ALEXANDER, SOUTHGATE and BASSINDALE 1935, etc.).
