Septa
Septa are internal, vertical, wall-like structures found within the shells of certain marine invertebrates, primarily cephalopods and some gastropods. These structures are composed of calcium carbonate and play a crucial role in providing structural support, compartmentalizing the shell, and regulating buoyancy.
Common Names
Septa are not commonly referred to by a specific name outside of scientific contexts. They are often described as "septa" or "partitions" within the shell of the organism.
Characteristics
Septa are typically thin, curved, and arranged in a series, dividing the interior of the shell into a series of chambers. The shape, size, and arrangement of septa can vary depending on the species and can be used for taxonomic identification. The outermost chamber, known as the body chamber, houses the living organism, while the inner chambers are typically filled with gas or liquid, which helps regulate buoyancy.
Environments
Septa are found in a wide range of marine environments, including shallow coastal waters, deep-sea trenches, and open oceans. They are particularly common in cephalopods such as ammonites, nautiloids, and squid, as well as some gastropods like the chambered nautilus.