Complex sentence: Being the principal division of the nervous system, it consists of a brain, a ventral nerve cord and a subesophageal ganglion which is connected to the brain by two nerves, extending around each side of the oesophagus.
Split into simpler sentences: Being the principal division of the nervous system, it consists of a brain, a ventral nerve cord and a subesophageal ganglion. This is connected to the brain by two nerves, extending around each side of the oesophagus.