The Collaborative International Dictionary
Ampullaceous
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.
Wiktionary
ampullaceous
a. Shaped like a swollen bottle.