Glossary
Like the rest of this website, the glossary is a work in progress. If we’ve missed a term, please contact us to let us know the term and references.
Cavum
A cavum is a silica extension found in some species of Planothidium, Gliwiczia and Skabitschewskia. The cavum partly covers the inside of the asymmetric central area of the rapheless valve in Planothidium and Gliwiczia. A cavum is present on both valves in Skabitschewskia.
See also rimmed depression.
Alternative Terms
- hood
Several references, use the Latin term "cavum" to describe this structure (including Kingston 2003). Other references, use the term "hood" (Round 1990).
Citations
Image Credit: Marina Potapova
Image Credit: Marina Potapova
Image Credit: Marina Potapova
A scanning electron micrograph of the inside of the rapheless valve of a species of Planothidium. The rounded, siliceous structure at the arrow is the cavum.
Image Credit: Marina Potapova
The rimmed depression and the edge of the cavum are visible in this light micrograph. The arrow rests on the open edge of the cavum.