Histological study of internal structure of sea anemones Anthopleura buddemeieri and Stichodactyla haddoni

Sea anemones (order Actiniaria) are among the most diverse and successful members of class Anthozoa, subclass Hexacorallia. According to the wonderful role of sea anemones as a benthic suspension feeding community and their ecological success by a propensity for engaging in symbiotic relationships and also their recent applications in biotechnology and the extraction of active biological substances and drug compounds, a study of internal structure of this aquatics is necessary. In this study, the histological sections with 5 µm thick were prepared from two species Anthopleura buddemeieri and Stichodactyla haddoni and stained with hematoxylin and eosin. By investigation of light microscope images, in both species the body wall and gastrovascular cavity were easily visible. Body wall significantly contained 3 layers of epidermis, mesoglea and gastrodermis and gastrovascular cavity structure included mesentery, longitudinal retractor muscles and parietobasilar muscles. In the species A. buddemeieri with making a histological section from all of the gastrovascular cavities of this animal, actinopharynx and siphonoglyphs were observed and the types and numbers of mesenteries were determined. Also in both species the longitudinal retractor muscles were stronger and wider attached to the end of primary and secondary mesenteries than pareitobasilar muscles placed near the body wall.