This image represents a view from the "front" of the neural system of a giant scallop, slightly turned, with the shell or "valve" hinge line at the top and open free margin along the bottom (this image shows what most observers might think of as a "side view" or "edge view"— see inset for orientation). The largest, most important ganglia are the parietovisceral (not the cerebral) which connect to the circumpallial nerve somewhat like an axle connects via spokes to the rim of a wheel. The circumpallial nerve forms a complete folded double ring around the edge of the animal's disk-like mantle inside each valve (mantle not shown here). The hundreds of nerves of the scallop's eyes and tentacles would have appeared as long thin lines jutting off along the entire length of this nerve like hazy fringe.Diagram: K.D. Schroeder