THE NUMBER OF GANGLION-CELLS IN THE INTACT AND REGENERATED NERVOUS-SYSTEM IN THE EARTHWORM (LUMBRICUS-TERRESTRIS)

1. The nerve cell number is higher in the cerebral ganglion than in th e subesophageal or segmental ganglia of Lumbricus terrestris. 2. The n erve cell number of the subesophageal ganglion is similar to that of t he segmental ganglia in spite that the latter developed from a fusion of several ganglia. 3. Segmental ganglia in front and behind the clite llum can be considered as ''typical'' ganglia. 4. The most caudal segm ental ganglia are less differentiated and resembles to the embryologic al state. 5. Nerve cells of the regenerating ganglia, at least in part , originate from undifferentiated nerve cells of the intact ganglia.