"Branch of Gulfweed (Sargassum bacciferum). a, vesicle with leaf; b, mucronate vesicle." -Whitney, 1911

Gulfweed Branch

"Branch of Gulfweed (Sargassum bacciferum). a, vesicle with leaf; b, mucronate vesicle." -Whitney, 1911

"Section of a pulmonary lobule, showing its division into pulmonary vesicles." — Tracy, 1888

Pulmonary lobule

"Section of a pulmonary lobule, showing its division into pulmonary vesicles." — Tracy, 1888