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855 



TERTIARY FAUNA OF FLORIDA 



Corbula (Cuneocorbula) Swiftiana C. B. Adams. 



Adams, Contr. Conch., xii., \i. 236, 1852; Dall, Bull. Mus. Comp. 

 Xool., ix., p. 114, 1881 ; xii., p. 314, pi. 2, figs. 5 a-c, 1886; Bull. U. S. Nat. Mus., 

 No. 37, p. 70, pi. 2, figs. 5 n-i , 1889; Harris, Bull. Pal., iii., p. 94, pi. 2, fig. 6, 

 1895. 



Typical form, recent from Cape Hatteras, North Carolina, to Venezuela. 

 Variety nuclcata Dall. Plate 36, figure 17. 



Miocene of the upper bed at Alum Bluff, Chattahoochec River, Florida; 

 Pliocene of Walton County, Florida, and Mrs. Guion's marl bed, on the 

 Waccamaw River, South Carolina. 

 Variety Harrisii Dall. 



Upper Miocene of the Galveston artesian well, from a depth of two 

 thousand nine hundred and twenty feet upward. 



The typical form of this species has rather irregular, sometimes rather 

 coarse, concentric sculpture, fainter near the beaks with faint traces of radi- 

 ating striae. When adult the rostrum, though small and narrow, projects 

 prominently and is squarely truncate ; the basal margin of the right valve is 

 very flexuous. 



In the variety nuclcata the shell is shorter, more globose ; the concentric 

 sculpture is nearly uniform and equally fine over the whole shell except the 

 extreme point of the beaks ; the rostrum is but little differentiated, short and 

 very obliquely, if at all, truncate. 



In the variety (?) Harrisii (Harris, op. cit., pi. 2, fig. 6) the shell is stated 

 to be fifteen millimetres long, which is nearly twice the size of the typical 

 Swiftiana, the rostral keel is much straighter, and the border less emarginate 

 below it than in the typical Swiftiana. It should be noted that specimens 

 closely agreeing with the recent shells, and some which resemble the variety 

 nuclcata, were also obtained from the well at various depths. 



The C. caribiea Orbigny is very close to C. Siviftiana, and is found recent 

 in the Antilles and has been reported by Guppy (1874) from the Pliocene of 

 Trinidad. If the two, on comparison of authentic examples, should prove to 

 be identical, Orbigny's name has seven years' precedence. 



Corbula (Cuneocorbula) contracta Say. 



Corbula contracta Say, Journ. Acad. Nat. Sci. Phila., ii., p. 312, 1822 ; Conrad, op. eft., 

 vii., p. 153, 1834; Gould, Inv. Mass., p. 43, fig. 37, 1841; Reeve, Conch. Icon., 



a, pi. iv., fig. 27, 1844. 



