PiNNIDAE 39 



worn shells; hinge area narrow, hinge teeth follow the rounded edge 

 of margin and incline obliquely outward; interior smooth, sometimes 

 purple stained; anterior margin crenate; impression of two adductor 

 muscles and pallial line present; no byssus. 



Dredged from sand and gravel bottom in three to six fathoms. 



Family PINNIDAE 



The Pinnidae are native to warm and temperate seas and mod- 

 erate depths. They live partly buried in the sea bottom, securely 

 anchored by a long-haired byssus, whose individual golden-brown 

 strands are so fine and silky that the nobility of ancient Greece 

 and Rome were proud to possess a garment woven from them. It 

 has been said that the Golden Fleece, which lured young Jason to 

 Colchis in the heroic days of Greece, was a garment made of the spun 

 byssuses of a Mediterranean species of this family. Gloves and other 

 articles made from byssuses of the same Pinna may be seen today in 

 Italy, but rather as objects of interest than as articles of luxurious 

 apparel. 



Extra large scallops offered in the markets are apt to be the ad- 

 ductor muscles of these mollusks masquerading as the true scallop 

 which is the muscle of Pecten. 



Black pearls are sometimes found in the mantle of Pinna or as 

 baroques on the nacreous lining of its valves. A little crab {Pinno- 

 theres) lives commensally in the mantles of Pinna and Atrina — 

 some old tales recite the benefit the crab was believed to bestow 

 upon its host by pinching him when a little fish entered between the 

 gaping valves. 



Shells of the Pinnidae are large, trigonal, with sharp apices at 

 the anterior extremities. Posterior borders extremely rounded and 

 somewhat gaping; dorsal margins straight or with slightly concave 

 curvature; ventral margins rounded; hinge teeth are present on the 

 dorsal margin, and a long linear ligament is lodged in a trench ex- 

 tending about two-thirds of the marginal length. The quality of the 

 shell is brittle and translucent, a nacreous layer which scales oflF 

 readily, covers about two-thirds of the interior of the valves. Im- 

 pressions of two muscles and pallial line are distinct. In the genus 



