A vocabulary of landscape — a landscape of words
1186 entries
cuttlebone
A cuttlebone is the internal shell of a cuttlefish, a light oval plate of aragonite built as hundreds of thin chambers separated by tiny pillars. The animal controls its depth by adjusting the ratio of gas to liquid in those chambers, which lets it hang motionless in the water without swimming. It is about 90 percent gas space by volume and is one of the most efficient natural buoyancy devices known. Cuttlebones wash up on beaches by the thousand.
Etymology
The first half of the word is Old English cudele, the animal, and its further origin is not established, though it may be related to a word for a bag or pouch, for the ink sac. The second half is misleading. There is no bone in it, and the plate is a shell that has migrated inside the body, the same evolutionary move that gave squid their internal pen.
Notes
Ground cuttlebone was used as a tooth powder and as a fine polishing abrasive, and jewelers still cast small silver pieces in it, pressing a model into the soft face to make a one-use mold. It is the standard calcium source hung in a bird cage. The chambered structure has been studied as a model for lightweight engineered materials.