torus
From ZooTerms (Dictionary of Invertebrate Zoology)
torus (noun; plural tori; Latin torus, swelling): 1. A blunt, rounded, ridge or protuberance.
2. (Annelida: Polychaeta) Low ridges provided with rows of acicular hooks or minute setae or uncini.
3. (Arthropoda: Insecta) In Diptera, the pedicel of the antenna.
4. (Porifera) A more or less doughnut-shaped space around the organism, concerned with water circulation.
