  Much effort has been made in trying to solve or at least evade the
inconsistencies that emerge from general relativity as the framework for a
cosmological model. The extradi- mensional models rise as superb possibilities
on this regard. In this work I present cosmo- logical solutions for Wesson's
Space-Time-Matter theory of gravity. A relation between mass variation at
cosmological scales and the expansion velocity of the universe is ob- tained.
Such a relation yields novel features on Space-Time-Matter theory of gravity,
which are carefully discussed.
