The Rock Oysters 



fighting conch (Strombus pugills). The area about the bases of 

 the spines is pecuharly pitted. Yellowish or white, stained with 

 pink. Lining usually orange. When grown together in a bunch 

 these mollusks modify or lose their spinous ornamentation. 

 Length, 2 inches. 



Habitat. — North Carolina to West Indies. 



The Large-leaved Chama (C. macrophylla, Chemn.) has a 

 yellowish shell lined with white. Irregularly distributed are 

 broad lamellar plates, like shingles, on both round valves. Pink 

 and violet specimens are found. The edges of the lamellae are 

 crimped minutely. This species lives a moderately free life. 

 Length, i to 2^ inches. 



Habitat. — Tampa to West Indies. 



The Frondose Chama (C. frondosa, Brod.) spreads over its 

 purple surface a series of broad, fan-shaped laminae, plaited and 

 imbricated, not too closely nor irregularly, producing an effect 

 of unusual richness. The colour is often brightened by yellow. 

 This is one of the largest and handsomest species. Length, 2 to 

 3 inches. 



Habitat. — Western Central America, Gulf of California. 



The Pretty Chama (C. piilchella, Rve.) daintily ruffled, 

 snow white, rayed with brown, and very compact of build, shows 

 a peculiarity of the genus. There are rights and lefts, specimens 

 showing opposite directions taken by the spiral beaks. This 

 is a variation due to conditions of growth. Length, i to 2 inches. 



Habitat. — New Holland. 



C. gyrphoides, Linn., of the Mediterranean Sea, so deeply 

 encrusts its thickly lamellate surface as to become very large 

 and heavy — a shapeless mass of lime — where two or more 

 are found together. Length, 3 to 4 inches. 



The Agate Chama (C. pellucida, Sby.) has its rough exterior 

 adorned by translucent frills, like rose agate or chalcedony. They 

 grow fast to rocks or other submerged objects. You may find 

 the upper valves on the beach. The china-white interior will 

 show a daintily crenulated pallial border. Length, 2 inches. 



Habitat. — Southern California. 



C. exogyra, Conr., a left-handed species, rough, opaque 

 and dirty white, occurs with its translucent relative, and looks 

 very unattractive by comparison. 



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