#trough shell

AKA duck clams.

The family have been around since the Cretaceous, living a short distance below the seafloor in sand or fine gravel. Each siphon has its own horny sheath.

AKA Mactra murchisoni, a large surf clam endemic to New Zealand.

The binomial honours German zoologist J.B. von Spix, and Sir Roderick Impey Murchison, a Scottish geologist who served as director-general of the British Geological Survey from 1855 until his death in 1871. The former generic epithet and the common name 'trough shell' are Greek for "kneading-trough" and also refers a large pit in the hinge line, where an internal ligament attachs.