air-sac

Updated: July 5, 2025

Many interesting stories of fishes can be told or read to the children, and among other things they can learn about the swim-bladder, the large, strong air-sac, which can be compressed or distended at pleasure, making the fish lighter or heavier and enabling it to rise to the surface of the water or sink to the bottom.

Margaret Warner Morley - The Renewal of Life; How and When to Tell the Story to the Young