Although I don't have an online reference for this, I do have a hard copy from some time back which claims the the amphioxus enteric nerve plexus is sensory rather than motor. I'll post this shortly.
by TC Lacalli - 2004 - Cited by 45 - Related articles - All 4 versions
Jun 9, 2004 ... Besides the oral plexus, plexus-like organization occurs widely in the peripheral tissues of amphioxus, especially in the gut and atrium ...
Need hard copy. Not in online abstract.
The oral nerve plexus in amphioxus larvae: function, cell types and phylogenetic significance
Link to abstract only, but I have the PDF & hard copy.