septum (coral)

{{Short description|Stony ridges forming part of the corallites of corals}}

In corals, a septum (plural septa) is one of the radiating vertical plates lying within the corallite wall. Outside the corallite wall these plates are known as costae (singular costa).{{cite book |title=Corals: A quick reference guide |last=Sprung |first=Julian |year=1999 |publisher=Ricordea Publishing |isbn=1-883693-09-8 |pages=220–223 }} The septa may be thick, thin or vary in size. They may have teeth which range from needle-like to blade-like and are often characteristic of different genera.{{cite web |url=http://www.coralhub.info/terms/septa/ |title=Septa |publisher=Coral Hub |accessdate=2015-04-22 |archive-date=2015-04-25 |archive-url=https://web.archive.org/web/20150425212042/http://www.coralhub.info/terms/septa/ |url-status=live }}