This class was created for the genus Neopilina, a mollusk discovered in 1952, when specimens were dredged from a deep trench off the Pacific coast of Central America. Neopilina displays primitive molluskan characteristics; it is the only mollusk with a segmented internal structure and is thought to show a relationship between mollusks and annelids. The animal is about 1 in. (2.5 cm) long and has characteristics of both chitons and gastropods, but does not quite fit into either class. A number of other species in several families have since been discovered or identified as belonging to this class.
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