radix
From ZooTerms (Dictionary of Invertebrate Zoology)
radix (noun; Latin radix, root): 1. A primary source.
2. (Arthropoda: Chelicerata) In Arachnida, apophysis of male copulatory organ.
3. (Echinodermata: Crinoidea) The rootlike distal anchorage of the stem; holdfast.
