The Collaborative International Dictionary of English v.0.48:

Badiaga \Bad`i*a"ga\ (b[a^]d`[i^][=a]"g[.a] or
   b[.a]d*y[aum]"g[.a]), n. [Russ. badiaga.] (Zool.)
   A fresh-water sponge (Spongilla), common in the north of
   Europe, the powder of which is used to take away the livid
   marks of bruises.
   [1913 Webster]