The Collaborative International Dictionary of English v.0.48:

Exaspidean \Ex`as*pid"e*an\, a. [Gr. ? out + ?, ?, a shield.]
   (Zo["o]l.)
   Having the anterior scutes extending around the tarsus on the
   outer side, leaving the inner side naked; -- said of certain
   birds.
   [1913 Webster]