ADDITION OF MESENTERIES DURING ASEXUAL REPRODUCTION OF THE POLYGLYPHIC SEA-ANEMONE ANTHOPLEURA-DIXONIANA (ANTHOZOA, ACTINIARIA)

Addition of mesenteries during asexual reproduction of the polyglyphic sea anemone Anthopleura dixoniana (Anthozoa: Actiniaria). Bull. Inst. Zool., Academia Sinica 32(2): 140-147. The mesenterial arrangement of the polyglyphic sea anemone Anthopleura dixoniana (Haddon & Shackleto n) during asexual reproduction was studied from November, 1987 through December, 1988. Individuals were collected from the upper intertidal zone at Wanlitung (120-degrees-41'E, 22-degrees-01'N) in southern Taiw an. In exocoels, two mesenteries were added in exocoels and developed into either directives or non-directive mesenteries. In a directive en docoel, two mesenteries with retractor muscles facing one another were added, resulting in two adjacent pairs of directive mesenteries; each pair consists of one new and one old member. In a non-directive endoc oel, four mesenteries were added, resulting in a pair of directive mes enteries flanked by two pairs of non-directives; each pair of non-dire ctive mesenteries consists of one new and one old member. Anthopleura dixoniana maintained a constant ratio between the number of non-direct ive and directive mesenteries among dividing, divided, and non-dividin g individuals. After division, two daughter A. dixoniana did not diffe r significantly in their numbers of mesenteries.