Three spectra of Pleione (1981, 1987-88, 1994), obtained in the blue w
avelength range, show strong long-term changes which indicate that the
surrounding shell, first rather cool and close to the central star, t
hen expands gradually in the equatorial plane of the star and towards
the poles. From 1981 to 1987-88, the spectrum of Pleione is that of th
e central star, with a cool shell which globally mimics a late-type st
ar. The year 1994 is marked by a pure and stronger Be spectrum, with n
o shell line.