  We study U-duality symmetries of toroidally compactified M theory from the
membrane worldvolume point of view. This is done taking the most general set of
bosonic background fields into account. Upon restriction to pure moduli
backgrounds, we are able to find the correct U-duality groups and moduli coset
parameterizations for dimensions D>6 as symmetries of the membrane worldvolume
theory. In particular, we derive the D=8 U-duality group SL(2)xSL(3). For
general background fields, we concentrate on the case D=8. Though the SL(2)
part of the symmetry appears to be obstructed by certain terms in the equations
of motion, we are able to read off the transformation properties for the
background fields. These transformations are verified by comparison with
11-dimensional supergravity dimensionally reduced to D=8.
