tropis
From ZooTerms (Dictionary of Invertebrate Zoology)
tropis (noun; Greek tropus, keel): 1. (Arthropoda: Crustacea) In Ostracods, a heavy chitinous (or two unfused rods) connecting the zygum to the sternix and pastinum.
2. (NEMATA: Adenophorea) In Enoplida, a hollow tooth-like structure formed by a subventral wall of the buccal capsule.
