fossula
From ZooTerms (Dictionary of Invertebrate Zoology)
fossula (noun; plural fossulae; fossule, fossulet; Latin diminutive fossa, ditch): 1. A shallow fossa.
2. (Arthropoda: Insecta) Grooves on the head or sides of the prothorax, in which the antennae are concealed; a foveola.
3. (Mollusca: Gastropoda) A shallow linear depression of the inner lip in some Cypraeidae.
