Abstract
Deformed salmon and trout have been described by Y. HANDA, P. D. MALLOCH and many others. But such is of rare occurrence in Plecoglosssus altivelis. In this paper are given mea-surements of five deformed specimens (Tab'es 1 and 2) and corresponding ones of two ordinary specimens (Tables 3 and 4) of this species obtained from the Yoichi River, Hokkaido in the summer of 1939. All the deformed ones were found sexnally mature.
