Barnacles represent a large group of crustaceans familar to most people who have visited the inter-tidal zones of the worlds oceans. A series of calcareous plates conceal the animal itself. There are typically six plates that overlap and interlock to create an igloo-like structure. The animal feeds by opening the plates and extends pairs of feathery cirri which trap suspended plankton and edible detritus.

The MBL collects various species of Balanus mostly from floats and pilings where they can be easily removed.

A related west coast species, B. nubilus, the giant Pacific barnacle, has the largest muscle cells known in the animal kingdom. These muscle cells are 2mm in diameter and 30 mm long and so are approximately 100 times larger than their mammalian counterparts. These cells may be dissected individually, cannulated to permit alterations of the ionic medium surrounding the contractile proteins, and are conveniently stimulated for hours in controlled perfusion media. These unique features have led to their use in basic muscle research.

Barnes, R.D., Invertebrate Zoology, 1980, Saunders College and Holt, Rinehart and Winston.