commissure
From ZooTerms (Dictionary of Invertebrate Zoology)
commissure (noun; Latin commissura, joint): 1. Connection between two bodies, structures, organs or nerve fibers; a junction, seam or closure.
2. (Arthropoda: Chelicerata) In Acari, the oral commissures.
3. (Mollusca: Bivalvia) The line of joining of the valves of the shell.
