This paper attempts to present a few hypothetical proposals on the internal structure of a sememe.A sememe in this paper means that of the sememic theory which was initiated by Dr.Hattori and has been expounded by Prof.Kunihiro. The writer tries to reinvestigate the internal structure of a sememe in terms of Chafe's notions of'directionality' and 'the primacy of semantic consideration,and introduces a distinction between'alterable features'(i.e.lexico-semantic features which,typically,vary in accordance with the shift of word-class,and which form the most common and superficial part of the lexico-semantic features)and'unalterable features'(i.e.lexico-semantic features which,typically,remain constant in spite of the shift of word-class, and which form the idiosyncratic and deep part of the lexico-semantic features).