central nervous system
From ZooTerms (Dictionary of Invertebrate Zoology)
central nervous system: In invertebrates, a system to which the sensory impulses are transmitted and from which motor impulses pass out. a. In radially symmetric animals, structured in the form of one or two rings. b. In elongate animals, usually consists of an anterior bilobed cerebral ganglion (brain), and paired longitudinal ventral cords that are usually connected by the circumesophageal nerve ring.
