Previous models of pursuit eye movements have foc ussed on reproducing the smooth eye velocity of monkey and human subjects and have not attempted to reproduce the discharge of neurons within the visual and motor pathways for pursuit. For example, the initial model proposed by Young et al (1968) and formalized by Robinson (1971) drove pursuit with a neural signal related target velocity so that model eye velocity could match target velocity without going into large, undamped oscillations. In a more modern version of the pursuit model, Robinson el al (1986) employed a feedback mechanism like that introduced in the "bang-bang" saccade model (Zee et al 1976). Proper adjustment of the parameters of the model allowed its output to reproduce all the features of the eye velocity evoked by a step change in target velocity in humans. Model eye velocity reproduced both the rising phase of eye velocity at the onset of pursuit and the frequency and amplitude of the oscillations of eye velocity during pursuit of sustained target motion. The key feature of Robinson's pursuit model is that the eye velocity command is delayed, filtered, and added to a signal related to retinal image velocity to develop an internal representation of target velocity.