OSTREIDAE 37 3 



similar to the Pacific Coast species. Inch-long, brownish specimens are fpund 

 in the crevices of coral boulders below low-water mark to several fathoms. 

 Larger, more whitish specimens are found clinging to iron wrecks. Moder- 

 ately common. P, decipiens Philippi. See plate 38b. 



SuperfavTily OSTREACEA 



Family OSTREIDAE 

 Genus Ostrea Linne 1758 



This genus used to include all of the oysters, but today several valid 

 genera are recognized, so that only three American species are included in 

 true Ostrea. These are O. eqiiestris Say and O. permolUs Sowerby from the 

 Atlantic Coast and O. hirida Carpenter from the Pacific Coast. The Euro- 

 pean oyster, O. ediiUs Linne is also in this group. All of these oysters are 

 relatively small. The eggs are fertilized and developed within the mantle 

 chamber and gills. Usually around one million eggs are produced at one 

 spawning. The prodissoconch hinge is long, the valves symmetrical. In the 

 adults, the muscle scar is near the center of the shell and is not colored. 



Ostrea equestris Say Crested Oyster 



Plate 28c 



North Carolina, Florida, the Gulf States and West Indies. 



I to 2 inches in length, more or less oval, and with raised margins which 

 are crenulated. The attached valve has a flat interior with a rather high, ver- 

 tical margin on one side. Interior dull grayish with a greenish or opalescent- 

 brown stain. Margin sometimes stained a weak-violet. Not very abundant 

 except in some Florida bays. It lives in water that is much saltier than that 

 in which virginica lives. Also named spreta Orbigny. O. cristata Born is 

 quite different and is limited to South America. 



Ostrea pons Linne 'Coon Oyster 



Plate 28d 



Florida, Louisiana and the West Indies. 



I to 2 inches in size. The radial plicate sculpture and corresponding 

 sharply folded valve margins are characteristic of this intertidal species. Inner 

 margins of valves closely dotted with minute pimples for nearly the entire 

 circumference of the valves. Muscle scars located well up toward the hinge. 

 Beaks somewhat curved. Interior translucent-white, exterior usually purplish 

 red. Frequently elongate and attached to stems of trees by a series of clasp- 

 ing projections of the shell, but may be also oval in shape. O. rubella and 

 O. limacella Lamarck are this species. O. jolimn Linne is a Philippine species. 



