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TERTIARY FAUNA OF FLORIDA 



usually somewhat distant, smooth, or faintly radially striated, except at the 

 extreme margin, where there are obsolete flutings on one or two of the outer- 

 most lamellae if any ; internal margins of the valves smooth ; average diameter 

 about twenty millimetres. 



Most of the specimens are somewhat worn, though the shell is abundant, 

 but it seems clearly distinct from C. chipolana. 



Chama draconis n. sp. 

 PLATE 56, FIGURES 17, 18. 



Oligocene of the Chipola marl, Chipola River, Calhoun County, Florida; 

 Burns and Dall. 



Shell irregular, attached by the anterior end of the right valve, which usu- 

 ally acquires a trigonal or semicircular outline ; sculptured on the right valve 

 with a curious, blistered verruculation not unlike convex scales of a saurian or 

 Gila monster, and also at the margin of the attachment with broad, irregular, 

 concentrically striated foliations ; on the posterior slope there is a tendency to 

 form two or three radial series of small, rather distant foliations, which, or 

 part of them, are often obsolete; near the posterior dorsal margin is a well- 

 marked radial sulcus and often another parallel to it but much more feeble; 

 left valve much flatter, irregularly concentrically lamellose, the lamellae rising 

 into foliations in two or three radial series behind, the foliations and most of 

 the surface with fine vermicular or partly divaricate radial fluting or threading ; 

 adductor scars small; internal margins finely crenulate. Average diameter 

 about twenty-five millimetres. 



This is a rather common species with a surface recalling that of Echino- 

 chama. 



Chama Lyelli n. sp. 

 PLATE 54, FIGURE 3. 



Oligocene limestone (horizon of Cerithium georgianum) of Jacksonboro', 

 ;orgia ; Vaughan and Whitfield. 



Shell of moderate size, represented only by casts, attached by the left valve; 

 the latter concentrically profusely lamellose, normal form rotund ; right valve 

 concentrically lamellose; the lamellae radially fluted, the alternate flutings 

 produced as long, smooth, radiating spines, sometimes half as long as the 

 diameter of the valve ; internal margin smooth. Diameter, excluding the spines, 

 about twenty-five millimetres. 



This species is imperfectly represented by the casts, but the sculpture is 

 unlike that of any other American species, recent or fossil, and will identify it. 



