part of embryonic gnathal neuromere embryonic fiber tract subesophageal embryonic fiber tract embryonic subesophageal commissure fly_anatomy.ontology A massive bundle of neurons in the embryo crossing the midline at the boundary between subesophageal and supraesophageal ganglia. It carries axons of mainly tritocerebral origin although some axons of neurons located in the mandibular neuromere also contribute to this commissure. VFB:FBbt_00001637 FBbt:00001637