overlaps larval visceral muscle cell FBbt:00001035 fly_anatomy.ontology FBbt:00005654 embryonic/larval visceral muscle cell Muscle cell of a muscle of the embryonic/larval intestinal tract. Circular and longitudinal fibers surround the entire intestinal tract, with the exception of the recurrent layer of the proventriculus. The circular fibers derive from a bilaterally symmetrical band of mesodermal cells extending continuously throughout most of the germ band. The longitudinal fibers derive from clusters of mesodermal cells which appear during stage 12 at the posterior end of the embryo and migrate anteriorly. larva visceral muscle cell larval muscle cell