FINN ID AE 359 



Family PTERIIDAE 

 Genus Pteria Scopoli 1777 



Fairly thin-shelled, moderately fat, and with the hinge ends considerably 

 drawn out. Pearly inside. The right and left valves bear i or 2 small denticles 

 which fit into shallow sockets in the opposite valve. 



Pteria colymbiis Roding Atlantic Wing Oyster 



Plate 35d 



North Carolina to southeast Florida and the West Indies. 



I /4 to 3 inches in length, obliquely oval with a long extension of the 

 hinge line toward the posterior end. Left valve inflated. Right valve 

 somewhat flatter and with a strong anterior notch for the byssus. Periostra- 

 cum matted, brown and with cancellate fimbrications. Exterior color vari- 

 able: brown, black or brownish purple with broken, radial lines of cream 

 or white. Interior pearly with a wide, non-pearly margin of purplish black 

 with irregular cream rays. Common from low water to several fathoms. 



The Western Wing Oyster, Pteria sterna Gould is very similar, 3 to 4 

 inches in length, and deep purplish brown with occasional paler rays. An- 

 chored in mud; from San Diego to Panama. Common. 



Genus Pinctada Roding 1798 



This is the famous genus of pearl oysters. The byssal gape is in the 

 right valve below the small, triangular auricle. Margaritifera Schumacher 

 is a synonym. 



Pinctada radiata Leach Atlantic Pearl Oyster 



Plate 35c 



South half of Florida and the West Indies. 



1% to 3 inches in length, moderately inflated to flattish, thin-shelled 

 and brittle. There is a small, thin, flat ligament at the center of the hinge. 

 Exterior tan with mottlings or rays of purplish brown or black. Rarely 

 tinted with dull-rose or greenish. In quiet waters, thin scaly and very deli- 

 cate, periostracal spines may be developed. Interior a beautiful mother-of- 

 pearl. Common in shallow water attached to rocks. 



Family PINNIDAE 

 Genus Pinna Linne 1758 



The Pen Shells are large, fragile, fan-shaped clams which live in sandy 

 or mud-sand areas, usually in colonies. The apex or pointed end is deeply 



