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1185 



TERTIARY FAUNA OF FLORIDA 



rad's work to which I have often had occasion to refer. The first Diplodonta 

 which received the name of parilis from Conrad was a species from the 

 Astoria beds of Oregon which figured under the generic name of Loripes in 

 1848 and was referred first to the Miocene and afterwards to the Eocene in 

 1865 under the generic name of Mysia. In 1860, however, he had described a 

 distinct species from the Cretaceous of Alabama as Mysia parilis. It turned out 

 to belong to the Veneridce, and Conrad proposed a genus Tenea for it in 1870, 

 while Gabb in 1876 showed that he had described the same shell in 1860 as 

 Mysia gibbosa, while Conrad as early as 1853 had named it Lucina pinguis. 

 Whitfield thinks Tenea practically identical with Thetis Sowerby, but at all 

 events it has a high angular pallial sinus and cannot be a Diplodonta. In addi- 

 tion to the above complications, in 1866 Conrad described a true Diplodonta 

 from the Miocene of Shiloh, New Jersey, as Mysia parilis. This has no con- 

 nection with the Oregon shell and requires a new name, which I have given it 

 as above. 



This species is rotund and turgid and clearly distinct from the later Miocene 

 species about to be discussed. There is a very closely related if not identical 

 form in the Jacksonian Eocene of Mississippi. 



Diplodonta nucleiformis Wagner. 



Mysia nucleiformis Wagner, Journ. Acad. Nat. Sci. Phila., viii., p. 52, pi. I, fig. 4, 1838. 

 Loripes elevata Conrad, Fos. Med. Tert, p. 73, pi. 41, fig. 8, 1845. 

 Cytherca sphatrica H. C. Lea, Trans. Am. Phil. Soc., 2d Sen, ix., p. 241, pi. 34, fig. 22, 



i84S. 



Diplodonta elevata Conrad, Proc. Acad. Nat. Sci. Phila., ix., p. 166, 1858. 

 Mysia carolincnsis Conrad, in Kerr, Rep. Geol. N. Car., App., p. 21, pi. 4, fig. 5, 1875. 



Miocene of Petersburg and York River, Virginia ; of the Meherrin and 

 Neuse River, of the Natural Well and Magnolia, Duplin County, North Caro- 

 lina, and in the Oligocene Oak Grove sands, Florida ; Wagner, Lea, Conrad, 

 and Burns. 



This is a smooth, moderate sized, globose species without any very dis- 

 tinctive characters, but smaller, less turgid, and transverse than D. shilohcnsis, 

 and more solid and circular than the following species. 



Diplodonta yorkensis n. sp. 



PLATE 43, FIGURE 5. 



Miocene of the York River, Virginia, near Yorktown ; Harris. 

 Shell thin, oblong, varying to rounded, sculptured only by incremental 



