The electroencephalographic responses in the rhombencephalectomized cat after the application of photic and epileptogenic agents resemble those phenomena in the normal animal. The spontaneous EEG of the motor region had fewer beta waves, a slower alpha but more delta components than the presection record. The response to photic stimulation in the occipital cortex was similar before and after the rhombencephalectomy, although the initial waves were slightly delayed. Epileptic activity upon topical application or intravenous administration of epileptogenic agents was demonstrated in the sensorimotor cortex.