''Arca imbricata'', or the Mossy ark clam, is a clam in the

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

Arcidae. It can be found along the Atlantic coast of North America, ranging from

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to the

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, and

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Description

''Arca imbricata'' grows to about 2 ins (5 cm) in length. The valves have a roughly rectangular shape with a rounded anterior end and a slightly pointed posterior end. They are usually purplish-white in colour, but live specimens are covered in a thin brown protective

periostracum The periostracum ( ) is a thin, organic coating (or "skin") that is the outermost layer of the shell of many shelled animals, including molluscs and brachiopods. Among molluscs, it is primarily seen in snails and clams, i.e. in gastropods an ...

. There are some distinct ribs on the posterior end and the margin is smooth. The hinge is long and straight with a number of fine teeth.Mossy Ark: Born to Shag
Retrieved 2011-11-29.

References

Arcidae Bivalves described in 1789 {{Arcidae-stub