Morphological synapomorphies that support anthozoan monophyly include the actinopharynx, which is an ectodermally-lined tube that extends from the mouth into the gastric cavity, the siphonoglyph, which is a ciliated groove in the actinopharynx, and the mesenteries, which are sheets of gastrodermal tissue that extend from the body wall into the coelenteron and have musculature of gastrodermal origin [18 ,22 ,23 ].
Source: wiktionary