WordNet (r) 3.0 (2006):

class Onychophora
    n 1: enigmatic small elongated wormlike terrestrial
         invertebrates of damp dark habitats in warm regions;
         distinct from the phylum Annelida; resemble slugs with legs
         and are sometimes described as the missing link between
         arthropods and annelids [syn: Onychophora, class
         Onychophora]