The structure of the ctenidium of the Japanese Scallop Patinopecten yessoensis was histologically examined. In the ventral bend, the principal and the ordinary filaments, joined each other by the cilia, were flattened and bent. The tip of the ventral bend had no specialized trough, nor the food groove. The inside surface of the dorsal bend formed the based ciliated tract and the outer surface was not fused to the mantle and visceral mass. In the inside of the dorsal bend, each vessel of the principal and the ordinary filaments are coupled together. The dorsal respiratory expansion was developed on the branchial cavity side of the principal filament. The vessel of dorsal respiratory expansion connects the vessel of principal filament and the inter-laminar connecting vessel. The lips are composed by two lobes of lip-apparatus on the upper lip and by three lobes of lip-apparatus on the lower lip. The lobes are composd of branched lobules on the lip-apparatus.
Japanese Scallop
dorsal respiratory expansion
dorsal bend of filament
inter-laminar connecting vessel
lobe of lip-apparatus
ventral bend of filament