Megathura crenulata, common name

Common name

A common name of a taxon or organism is a name in general use within a community; it is often contrasted with the scientific name for the same organism...

 the "great keyhole limpet" or "giant keyhole limpet", is a species of limpet

Limpet

Limpet is a common name for a number of different kinds of saltwater and freshwater snails ; it is applied to those snails that have a simple shell which is more or less conical in shape, and either is not spirally coiled, or appears not to be coiled in the adult snails.The name limpet is most...

 in the family Fissurellidae. These keyhole limpets are large, growing up to 60-132 mm. They are found in the Eastern Pacific.

Megathura is a monotypic genus, in other words, this is the only species in that genus.

Keyhole limpet hemocyanin

Keyhole limpet hemocyanin

Keyhole limpet hemocyanin

Keyhole limpet hemocyanin is a large, multisubunit, oxygen-carrying, metalloprotein found in the hemolymph of the giant keyhole limpet, Megathura crenulata, that lives off the coast of California from Monterey Bay to Isla Asuncion off Baja California.-Protein properties:Keyhole limpet hemocyanin...

 from Megathura crenulata is used as vaccine

Vaccine

A vaccine is a biological preparation that improves immunity to a particular disease. A vaccine typically contains an agent that resembles a disease-causing microorganism, and is often made from weakened or killed forms of the microbe or its toxins...

 carrier protein

Carrier protein

Carrier proteins are proteins involved in the movement of ions, small molecules, or macromolecules, such as another protein, across a biological membrane. Carrier proteins are integral membrane proteins; that is they exist within and span the membrane across which they transport substances. The...

.