  Some systematic general features of y-scaling structure functions, which are
essentially independent of detailed dynamics, are pointed out. Their physical
interpretation in terms of general characteristics, such as a mean field
description and nucleon-nucleon correlations, is given and their relationship
to the momentum distributions illustrated. A new scaling variable is proposed
which allows a direct expression of the scaling function in term of an integral
over the momemtum distributions thereby avoiding explicit consideration of
binding corrections.
