Anatomical Structure of Ctenidium in the Japanese Short-neck Clam Ruditapes philippinarum

アサリの鰓構造

Anatomical Structure of Ctenidium in the Japanese Short-neck Clam Ruditapes philippinarum

Creators Yamamoto Ken-ichi

Creators Araki Akira

Creators Handa Takeshi

The structure of the ctenidium in the Japanese short-neck clam Ruditapes philippinarum was examined. The inner ctenidium is larger than the outer ctenidium. Only the inner ctenidium has reached the lateral oral groove into the labial palp. The ascending lamella of outer ctenidium (the outer lamella of outer ctenidium) has formed the supra-axial extension of ascending lamella of outer demibranch near the dorsal edge by greatly expanding the base. Both outer and inner ctenidia each have the food groove. The observation of the cross section of the ctendium revealed that the ordinary and the principle filaments have joined in a semicircular shape by the interfilamentar junction, or the intra-plical bond and that the ordinary filaments near apex have formed a circular dead space (the inter-filament space). The intra-plical bond has been bonded with the inter-filament connecting membrane (expect for the inter-filament space). The type of the principle filament was the frontal ridge of principle filament. The position where the inner lamina of outer ctenidium and the outer lamina of inner ctenidium joined has formed the based ciliated tract of inner and outer laminae of ctenidia, whereas in the bases of the outer lamella of outer ctenidium and the inner lamina of inner ctenidium, no based ciliated tract has been formed. In the labial palp, the direction of the filaments of the inner ctenidium is parallel to the lateral oral groove.

[ISSN]0370-9361