part of glial cell surface glial cell perineurial glial cell outer perineural sheath cell PNG FBbt:00005153 perineural cell perineurial sheath cell apical glial cell fly_anatomy.ontology Glial cell that forms part of the perineurial sheath forming the outer layer of the nervous system. These cells divide extensively to increase in number as the nervous system expands during development (Kremer et al., 2017). perineurial glia VFB:FBbt_00005153 perineurial sheath glial cell perineurial glial sheath