These blinds are constructed with sliding frames, having small squares of two inches filled in with a thin semi-transparent shell, a species of placuna; the fronts of some of the houses have a large number of these small lights, where the females of the family may enjoy themselves unperceived.
"The Former Philippines thru Foreign Eyes"
Tomás de Comyn Fedor Jagor Rudolf Ludwig Carl Virchow Charles Wilkes
So prolific are the mollusca of the placuna, that the quantity of shells taken by the licensed renter in the three years prior to 1858, could not have been less than eighteen millions.
"Sketches of the Natural History of Ceylon"
J. Emerson Tennent
placuna 4 Scinde, North Australia, China-in brackish water.
"Sea-Weeds, Shells and Fossils"
Peter Gray B. B. Woodward