  We study various $Sp(2M)$ invariant field equations corresponding to rank $r$
tensor products of the Fock (singleton) representation of $Sp(2M)$. These
equations are shown to describe localization on ``branes'' of different
dimensions embedded into the generalized space-time $\M_M$ with matrix (i.e.,
``central charge'') coordinates. The case of bilinear tensor product is
considered in detail. The conserved currents built from bilinears of rank 1
fields in $\M_M$ are shown to satisfy the field equations of the rank 2 fields
in $\M_M$. Also, the rank 2 fields in $\M_M$ are shown to be equivalent to the
rank 1 fields in $\M_{2M}$.
