contained in develops from existence overlaps material entity inner longitudinal muscle cell inner longitudinal muscle layer Planarian_Anatomy https://orcid.org/0000-0003-2569-1939 | https://orcid.org/0000-0002-7535-4407 ISBN:9780070316607 https://github.com/obophenotype/planaria-ontology/blob/master/metadata/planarefs/planaref-0000003.md Inner most body wall muscle fibers arrayed along the anteroposterior axis. These fibers are thicker than the outer longitudinal muscle fibers. The pattern of these muscles differs along the dorsoventral axis, with the dorsal arrangement converging at the central zone of the anterior pole. The ventral arrangement is more parallel or may diverge slightly as it approaches the ventral pole. PMID:26904543 inner longitudinal muscle fiber PMID:30962434 longitudinal muscle cell longitudinal muscle progenitor cell anterior region of the whole animal dorsal region of the whole animal posterior region of the whole animal ventral region of the whole animal juvenile stage head region prepharyngeal region parapharyngeal region tail region adult hermaphrodite asexual adult copulatory region