Source : Webster's Revised Unabridged Dictionary (1913)

Ampullaceous \Am`pul*la"ceous\, a. [L. ampullaceus, fr.
   ampulla.]
   Like a bottle or inflated bladder; bottle-shaped; swelling.
   --Kirby.

   {Ampullaceous sac} (Zo["o]l.), one of the peculiar cavities
      in the tissues of sponges, containing the zooidal cells.