part of overlaps larval circulatory system embryonic/larval dorsal vessel A contractile tube in the embryo/larva that extends from immediately behind the posterior commissure of T1 to the arthrodial membrane of A7, into which it inserts via two caudally directed muscles which connect to lateral apodemes in A8. Throughout its length, its lumen is enclosed by just two cardial cells. This single-cell thick layer of cardial cells is surrounded by a single-cell thick layer of pericardial cells, except in the posterior thorax. In this region, it is surrounded by lymph gland in the anterior thorax where it passes through the ring gland. The whole tube is attached to the anterior region of each abdominal segment boundary by alary muscles. FBbt:00005681 fly_anatomy.ontology FBbt:00001673 larval dorsal vessel larva dorsal vessel