Units responding to manual stretch of single eye muscles were localized in the mesodiencephalic region of the lamb. Responses of the type induced by muscle spindle excitation were recorded from ipsilateral medial lemniscus, tegmentum and tectum of both colliculi and from ipsilateral posteroventrolateral nuclei of the thalamus. From the same mesodiencephalic points activated by stretch of individual eye muscles typical evoked potentials could be recorded following single-shock electrical stimulation of the ipsilateral sites of the pars oralis of the descending trigeminal nucleus, of the homonymous tract and of the main sensory trigeminal nucleus in which the eye muscle proprioception is represented. The latency of such evoked potentials was very short (0.33-1 msec), showing that no synapse oronly one synapse was intercalated between the stimulated and the recorded points. The conclusion was reached that the axons of the second-order neurons of the extraocular muscle proprioception located in the pars oralis of the descending trigeminal nucleus and in the main sensory trigeminal nucleus project through the medial lemniscus on the tectum and tegmentum of the mesencephalon and on the posteroventrolateral nuclei of the thalamus.