Abstract
1. Investigations were made on the nervous system of Onchidium verruculatum, pulmonate mollusc. A microelectrode was inserted into the soma of the giant neuron on the dorsal surface of the perioesophageal ganglion complex in order to record the change in membrane potential.
2. Peripheral nerve trunks were stimulated electrically through bipolar electrodes. Each peripheral stimulus evoked the change in the membrane potential which were averaged by the digital computer, LINC-8.
3. The analysis of the averaged responses could disclose the modes of synaptic connections, including a direct connection; i. e. an axon or an axonal branch.
4. On the basis of the averaged responses, neuronal connections were deduced between peripheral nerve trunks and ganglion cells which could be always identified under a binocular microscope.
5. The possibility and the limitation of the averaging technique are discussed.
