Search Result for "anaspid": 
Wordnet 3.0

NOUN (1)

1. extinct small freshwater jawless fish usually having a heterocercal tail and an armored head; of the Silurian and Devonian; 



WordNet (r) 3.0 (2006):

anaspid
    n 1: extinct small freshwater jawless fish usually having a
         heterocercal tail and an armored head; of the Silurian and
         Devonian