LARVAL DEVELOPMENT OF OCTOMERIS-SULCATA NILSSON-CANTELL (CIRRIPEDIA, THORACICA, CHTHAMALIDAE) FROM JAPAN AND KOREA

Embryos obtained from gravid adults of the chthamalid barnacle Octomer is sulcata Nilsson-Cantell from Japan and Korea were cultured through six naupliar stages to the cyprid and juvenile barnacle stage in labor atory conditions, fed either the diatom Skeletonema costatum (Grev.) C leve or the dinoflagellate Prorocentrum minimum (Pavillard) Schiller. The nauplii were planktotrophic and, depending on diet, reached the cy prid stage 9 or 17 days after hatching in individual cultures at 22 de grees C with 24 h illumination. The survival rate was higher and the d uration of the naupliar stages was shorter when fed P. minimum rather than S. costatum. This is probably due to the presence of feathered se tae on the antennae. Feathered or plumose setae in nauplii of differen t cirripede taxa are apparently linked to the type of phytoplankton in the seas when these taxa first evolved. The larval stages of O. sulca ta are described, and morphological differences between larvae reared from Japanese and Korean adults are compared. The polygonal cephalic s hield and unilobed labrum, a pair of posterior shield spines after nau pliar stage IV, feathered setae and a hispid seta on the coxa of the a ntenna, a cuspidate seta on the mandible, and the gnathobase of the an tenna are important in distinguishing the nauplii of this species from other species, including Chthamalidae.