The structure of the ctenidium of the Noble scallop Mimachlamys nobilis was histologically examined. In the ventral and the dorsal bends, 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, or the food groove. In the dorsal bend region the inside surface of the sickle-shaped tip formed the based ciliated tract, whereas the outer surface of that was not fused to the mantle and visceral mass. The dorsal respiratory expansion was contained within the wall of the principal filament of from the proximal to about half. The inside of the expansion was comprised of the tabular blood vessels which exhibited the similar architecture of the inter-laminar connecting vessels. The lips were composed by two lobes of lip-apparatus of the upper lip and by three lobes of lip-apparatus of lower lip, and the upper lip and the lower lip were engaged each other securely. The inside surface of the lips and the lobes was covered with the cilia.
Noble scallop
dorsal respiratory expansion
dorsal bend of filament
inter-laminar connecting vessel
lobe of lip-apparatus
ventral bend of filament.