Britannica
Sources used in this answer
How does a lamp shell’s mantle produce its shell?
Created from Britannica articles
using AI.
AI can make mistakes, so verify using Britannica articles.
lamp shells
Lamp shells on the sea floor off the coast of Massachusetts.
The mantle of a lamp shell (brachiopod) is a thin, soft covering formed from the body wall that is responsible for secreting the animal's shell. This mantle is divided into dorsal and ventral lobes, which are covered with small, nipple-like projections called papillae that penetrate into the shell structure.12
In articulate brachiopods, the mantle secretes a shell typically composed of three distinct layers:2
- Periostracum: The outermost layer, which is made of organic substances.2
- Middle layer: Composed of calcium carbonate in the form of calcite.2
- Inner layer: Also composed of calcite fibers, which may be perforated by minute pits (punctate) or contain vertical calcite rods (pseudopunctate).2
The mantle remains in contact with the shell interior, lining the mantle cavity, and is fringed at its edges by bristle-like structures called setae.2