A multisomatic axon in the central nervous system of the leech.

There is one particularly large axon in the medial bundle of the nerve cord of the leech. It extends along the entire length of the cord and is connected to a single cell body in each ganglion. The cell bodies in adjacent ganglia are tightly electrically coupled, and dye injected into one cell body can diffuse along the axon and into the cell body of the next ganglion. If the nerve cord is cut between two ganglia, neither end of the axon degenerates. Repair of the axon appears to occur by end-to-end fusion.