Balanus glandula

The Acorn Barnacle

Phylum Arthropoda
Subphylum Crustacea
Class Maxillopoda
Subclass Cirripedia
Order Thoracica
Family Balanidae
Genus Balanus
Species glandula

Description: Size can reach 1.5 cm; grayish-white and smooth; sinuous line separating the two smaller plates from the two larger plates; height is equal to diameter unless animals are crowded, then they are almost columnar.

Habitat: Found on floats, pilings, rocks, shells, kelp, driftwood, boats and the backs of crabs.

Natural History: As the most abundant barnacle, it produces clouds of larvae that other plankton-eaters feed upon. It is primarily preyed upon by Pisaster sea stars and Nucella whelks.