Biology and Anatomy. In various animals and plants: a bladder or sac filled with air or gas, as those in floating algae.
A swimming organ of an animal; esp. an anal appendage in certain aquatic insect larvæ. (Cf. swimmeret, n.)
A floating appliance for supporting something in the water. A hollow or inflated part or organ that supports an animal in the water. Hence used in…
a bell-shaped part or organ, as a nectocalyx, by which an animal propels itself through the water.