The neural connection between the Langerhans receptor cells and the central nervous system in Oikopleura dioica (Appendicularia)

Summary Transmission electron microscopic analysis of serial sections showed that the receptor cells are innervated by only one neuron and not two as previously believed. The neuron's two dendrites constitute the afferent sensory nerves to the caudal ganglion where the neuron's cell body is located. Its neurite was traced a few micrometers, but the synaptic terminals were not identified. This sensory system in Oikopleura is compared with a similar caudal sensory system in the tadpole larva of Diplosoma macdonaldi investigated by Torrence and Cloney. Wiring diagrams are proposed for the two systems. The ganglia, which receive the afferent sensory neurons, are discussed in terms of models for further research on simple integration systems.