Amphibalanus improvisus

Bay barnacle
Scientific classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Arthropoda
Class: Thecostraca
Subclass: Cirripedia
Order: Balanomorpha
Family: Balanidae
Genus: Amphibalanus
Species:
A. improvisus
Binomial name
Amphibalanus improvisus
(Darwin, 1854) 

Amphibalanus improvisus, the bay barnacle, European acorn barnacle, is a species of acorn barnacle in the family Balanidae.