  In this article we use a Prym construction to study low dimensional abelian
varieties with an action of the quaternion group. In special cases we describe
the Shimura variety parameterizing such abelian varieties, as well as a map to
this Shimura variety from a natural parameter space of quaternionic abelian
varieties. Our description is based on the moduli of cubic threefolds with nine
nodes, which we study in some detail.
