Menesiniella aquila
Menesiniella aquila is a species of acorn barnacle in the family Balanidae. It is found off the California coast from San Francisco to San Diego from the bottom of the intertidal zone down to depths of 18 m. It is preyed upon by fish, sea stars, and certain carnivorous snails. Fish also rub against the barnacles to clean themselves of parasites, which wears the barnacles shells to a smooth surface. This species was formerly a member of the genus Balanus. References

Barnacles
Endemic fauna of California
Endemic crustaceans of the United States
Crustaceans of the eastern Pacific Ocean
Crustaceans described in 1907
Taxonomy articles created by Polbot
Taxobox binomials not recognized by IUCN 
Fauna without expected TNC conservation status