Velum

From Wikipedia, the free encyclopedia

The term, velum, derived from Latin velum, meaning a "sail", "curtain," "awning" or "veil", has several quite separate meanings in biology:

• the locomotory and feeding organ provided with cilia found in the larval stage called the veliger or "velum-bearing" stage of bivalves, such as mussels and oysters; also a delicate membrane found on certain Protists.

• the circular membrane round the cap of a sea jelly or medusa of class Hydrozoa

• the veil-like membrane of immature mushrooms extending from the margin of the cap to the stem and torn by growth, revealing the gills of a mature sporophore; in a mature mushroom, the remains of the velum may form an annulus or ring around the stem, familiar from common button mushrooms and sometimes on the margin of the cap.

• the soft palate behind the hard palate

• Velum is also a common misspelling of vellum, pigskin with which books were once covered. Today, Leatherette, leather, cloth or paper are more commonly used.