Volcano Barnacle (Tetraclita sp.)
Barnacles are crustacea and not molluscs. In their larval stage, they look like tiny shrimps.
When a larvae finds a good spot to settle down, it releases cement from the
tips of its first pair of antennaes and glues itself head down on the surface.
It then secretes a thick shell made up of a series of plates.
Inside the shell is a segmented body and six pairs of segmented legs modified
into feathery appendages. At high tide, the animal waves its legs outside
the shell to filter feed and breathe, as the legs also contain the gills.