catadromous, a. [Gr. kata` down + dro`mos a running.].
Having the lowest inferior segment of a pinna nearer the rachis than the lowest superior one; -- said of a mode of branching in ferns, and opposed to anadromous. [1913 Webster]
Living in fresh water, and going to the sea to spawn; -- opposed to anadromous, and said of the eel. [1913 Webster]