part of adult cardial valve adult visceral muscle cell adult cardial valve muscle cell https://github.com/FlyBase/drosophila-anatomy-developmental-ontology/issues/24 FBbt:00007043 Cell that is part of a layer of longitudinal muscle fibers found between the inner and intermediate layers of the adult proventriculus (cardia). These muscle fibers are embedded in an extracellular matrix that fills the available space. hilus fly_anatomy.ontology