The Collaborative International Dictionary of English v.0.48:

Physostomous \Phy*sos"to*mous\ (f[i^]*s[o^]s"t[-o]*m[u^]s), a.
   (Zool.)
   (a) Having a duct to the air bladder.
   (b) Pertaining to the Physostomi.
       [1913 Webster]