Like higher animals it has a nerve cord, muscles, and a gut, with a brain at the mouth (hardly a head) end.

From the ganglion there are two nerve cords which extend the length of the tail.

Early in the evolutionary process, however, the nerve cords became more than simple cords.

The nervous system of an insect can be divided into a brain and a ventral nerve cord.

Extending from the brain is a large ventral nerve cord running the length of the body.

Above it is a nerve cord with a single frontal eye.

Second, they possess a hollow nerve cord down the back, just under the notochord.

All other phyla have a solid nerve cord running down the abdomen.

Last of all, it has a paired ventral nerve cord.

In the early embryonic stage it looks like the hollow nerve cord of chordates.