The nervous system of the early echinopluteus.

An ectodermal network of nerve cells has been observed in the echinopluteus. It seems to connect the ectodermal cell bodies with each other and with deeper parts of the nerve system. Together with the neurohumour containing parts of the ventral and oral ciliated bands, the nerve cells probably provide the larva with the capacity of coordinating muscular and ciliary responses to mechanical, chemical and electrical stimulation.