关键词: 西施舌, 幼虫, 附着变态, 胚后发育, Coelomactra antiquate, larvae, attachmet metamorphosis, postembryonic development

Abstract: From 1999 to 2011, during the period of artificial breeding of Coelomactra antiquate, in order to enrich its larvae metamorphosis biology theoretical basis and improve the seeding rate, the author took methods of micro continuous observation and microscopic photography in vivo, studying on the morphological characteristics of Coelomactra antiquate veliger during the various stages, as well as the whole process of attachment metamorphosis and postembryonic development. The results showed that linear hinge of Coelomactra antiquate larve for combined individual size was 72μm ×55μm ~ 106μm ×94μm, and the anterior adductor muscle and 3 pairs of retractor muscles of veliger larva appeared. The umbo veliger larvae began to generate rear adductor muscle. Therewas one pair of balancer above the node of foot the center of velum has flagellate. The post larvae appeared byssus gland and internal gill filament. Creeping larva foot showed rod-like structure, creeping activity was frequent, byssus gland developed and there were 2~3 pairs of internal gill filament. Velum atrophied, flagellate shed, and began to secrete byssal attachment. Then shell formed, organ shifted, and lip and mouth was connected with gill filaments. Eating through gill was the main biological symbol of metamorphosis of Coelomactra antiquate larvae. The labellum of early young shell was two finger shape, and there were 2~4 pairs of the internal gill filament. The labellum of early juvenile shell was triangular shape, eye spot disappeared, and the outer gill filaments appeared. Internal organ development was complete except reproductive organs. The study has important significance for induction and attachment of coelomactra antiquate larvae and perfection of the industrial breeding technology.