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1401 



TERTIARY FAUNA OF FLORIDA 



spinules. It is usually attached by the beak of the left valve, which is quite 

 turbinate, a single valve recalling a specimen of Neritopsis. The average diam- 

 eter is about twenty-eight millimetres, and the internal margins are crenulated. 

 This appears to be the species said to be abundant in Cuba, which is cited 

 by Arango (p. 272) as Chama foliacea Gmelin, based chiefly on Lister's figures. 

 It is, however^ too uncertain to be adopted even if the specific name was not so 

 glaringly inappropriate. 



Chama striata Emmons. 



Chama striata Emmons, Geol. Rep. N. Car., p. 286, fig. 211, 1858; Conrad, Proc. Acad. 

 Nat. Sci. Phila. for 1863, p. 576, 1864; Meek, Checkl. Miocene Fos. N. Am., p. 8, 

 1864. 



Upper Miocene of North Carolina at the Natural Well and Magnolia, Duplin 

 County ; of Florida, sixteen miles southwest of Tallahassee ; Pliocene of Tilly's 

 Lake, Waccamaw district, South Carolina, and of Shell Creek and the Caloosa- 

 hatchie River, Florida. 



A small species attached by the left valve with a strong sulcus near the pos- 

 terior dorsal margin of that valve ; the free valve obscurely divided into three 

 lobes by two broad, shallow, radial sulci on the posterior half of the shell ; the 

 sculpture is of fine flutings with occasionally two or more radial series of small, 

 distant, squarish foliations. The margins are finely crenulate and the average 

 diameter is about twenty millimetres. The adductor scars are rather long. 



Emmons' figure is quite inadequate to give any sufficient idea of the species. 

 It may prove to be a dynamic mutation of some other species, but Emmons, 

 Meek, and Conrad, all good judges, regarded it as distinct. 



Chama Willcoxii Dall. 

 PLATE 41, FIGURES 5, 6, 7. 

 Chama Willcoxii Dall, Trans. Wagner Inst., iii., p. 1197, pi. xli., figs. 5, 6, 7, 1900. 



Pliocene of the Caloosahatchie beds on the Caloosahatchie and Shell Creek, 

 Florida ; Willcox, Burns, and Dall. 



Shell large, solid, lamellose, normal or attached by the left valve; beaks 

 prosogyrate, their coil forming about two turns; both valves with a strong 

 furrow extending from the beaks to the lower posterior margin, but more or 

 less obscured by the lamellation; both valves similarly sculptured with nu- 

 merous, close-set, arched lamellae more or less fimbriated, sharply, closely, 

 radially grooved on the upper surface, and for the most part distally appressed 

 towards the valve, especially on the fixed valve, the under surfaces concave or 



