Velocity fluctuations and hydrodynamic dispersion are studied in a monodisperse dilute suspension of rigid spherical particles. In the absence of Brownian motion and inertia, fluctuations in the velocity of individual particles arise from hydrodynamic interactions varying with the ever-changing configurations of the particles. We show some computer simulations of point particles with excluded volume sedimenting in a rectangular container with periodic sides and impenetrable bottom and top. The simulations reproduce the experimental correlation-time and anisotropy of the velocity fluctuations but have a magnitude increasing proportionally to the size of the system.