rachidian การใช้

• Most importantly, the mouthparts contain a central rachidian tooth a key radular characteristic.
• Radula : the rachidian tooth is broader than high and has the lateral wings prominent.
• There is a quadricuspid rachidian tooth, the two main cusps being asymmetrical and aculeate.
• Radula : the rachidian tooth is higher than broad and has lateral wings reduced or absent.
• The radula contains a rachidian tooth when fully developed, but this is vestigial in some species.
• The central rachidian is heart-shaped, narrow free end surmounted by small, slightly serrated denticle.
• The single rachidian tooth is flanked on each side by one rhomboidal lateral tooth and two long, hook-like marginal teeth.
• The radula is typically taenioglossate with one central ( rachidian ) tooth, with on each side one lateral tooth and two marginal teeth.
• This particular formula, which is common to the scaphopods, means one marginal tooth, one lateral tooth, one rachidian tooth, one lateral tooth, and one marginal tooth across the ribbon.
• The rachidian tooth has two long main cusps and might have a denticle between them, with one to two cusps to the side of the left main cusp and one to the side of the right one.