collarette
From ZooTerms (Dictionary of Invertebrate Zoology)
collarette (noun; Latin diminutive collare, band for the neck): 1. (Chaetognatha) Thickened distended cells in the neck region that in some species extend posteriorly along the trunk for some distance; in one instance as far as the lateral fins.
2. (NEMATA) Either anterior or posterior cuticular extensions forming an annular ring in the neck region.
