Source : Webster's Revised Unabridged Dictionary (1913)

Astomatous \A*stom"a*tous\, Astomous \As"to*mous\, a. [Gr. 'a
   priv. + ?, ?, mouth.]
   Not possessing a mouth.

Source : WordNet®

astomatous
     adj : having no mouth or mouthlike opening [syn: {mouthless}]
           [ant: {stomatous}]