In this Annelid later the sac in question joins its fellow, passing beneath the nerve cord exactly as in the leech, and also grows out to reach the exterior.
There is a welldeveloped brain dorsal, to the mouth; this gives off a pair of oesophageal commissures, which surround the oesophagus and unite in a median ventral nerve-cord which runs between the longitudinal muscles to the posterior end of the body.
Strands breaking up the f, Ventral nerve-cord.
There is a single unsegmented nerve-cord which runs along the ventral middle line and enlarges posteriorly into a caudal ganglion and anteriorly in a ganglion, the brain, which is not supra-oesophageal.
For the sake of uniformity in nomenclature this nerve-cord may be called the neurochord.
