Ryan Photographic - Pinnidae - Pen shells
Family Pinnidae
The family Pinnidae contains 57 species in 3 genera. They are called pen shells because of their shape - somewhat reminiscent (only somewhat) of old-fashioned quills. They range in size but most are large with the biggest, the Mediterranean-dwelling Pinna nobilis, reputed to reach 120 cm. The byssus threads of P. nobilis were collected, spun, treated with lemon juice and made into extremely fine garments such as stockings or gloves. You can read more about sea silk here. Apparently Jules Verne clothed the mariners in 20,000 leagues under the sea in "sea silk".
The adductor nuscles of pen shells are eaten in many cultures and some species produce pearls of mediocre quality.
Atrina pectinata Comb pen shell
Atrina pectinata Comb pen shell, Puerto Galera, Philippines IMG_7439
Atrina zelandica New Zealand horse mussel
Atrina zelandica New Zealand horse mussel