TRANSACTIONS OF WAGNER 

 990 



TERTIARY FAUNA OF FLORIDA 



to be obsolete behind the posterior fold; the surface is also concentrically 

 striated ; hinge strong, normal ; beaks not prominent ; pallial sinus short, 

 rounded, ascending towards the umbo and not extending behind a vertical 

 therefrom. Alt. 6.5, lat. 8.0, diam. 3.5 mm. 



This stout, strongly sculptured little shell recalls the young of carinata, but 

 is much more inflated, solid, and more coarsely sculptured. 



Semele subovata Say. 

 Amphidesma subovata Say, Journ. Acad. Nat. Sci. Pliila., iv., p. 152, pi. 10, fig. 10, 1824; 



Conrad, Fos. Medial Tert, p. 36, 1840. 

 Syndosmya subobliqua Conrad, Proc. Acad. Nat. Sci. Phila., vii., p. 29, 1854 (lapsus for 



subovata). 

 Abra ovalis Conrad, Proc. Acad. Nat. Sci. Phila. for 1862, p. 288, 1863. 



Miocene of the Choptank River, Maryland ; of Petersburg, Virginia ; of 

 the Yorktown beds along the York River, Virginia ; and of the artesian well 

 at Galveston, Texas, between two thousand five hundred and fifty-two and two 

 thousand six hundred feet below the surface. 



This is a common species of the Virginia Miocene, separable from the S. 

 carinata, which is almost equally common, by its more oval and thinner shell, 

 and finer, sharper, and closer concentric sculpture. The posterior dorsal area 

 is usually conspicuously sculptured, while in ^. carinata the tendency of the 

 sculpture on this area is to become obsolete. 



Semele bella Conrad. 

 Abra bclla Conrad, Kerr, Geol. N. Car., App., p. 19, pi. 3, figs. 4, 6, 1875. 



Miocene of North Carolina at Wilmington, and in Duplin County, at and 

 near the Natural Well ; Conrad and Burns. 



This species exhibits much such a series of mutations as 5". mutica of the 

 Oligocene. It is nearly the shape of 6". srcbovata and may be separated into 

 three principal varieties by its sculpture : 



Variety duplinensis Dall. This form has close set, elevated, concentric, sharp 

 lamellas, with no radial sculpture. Duplin County, North Carolina. 



Variety appressa Dall. In this the concentric lamellae are appressed to the 

 surface, forming narrow, flatfish waves, much as in 5". carinata var. compacta, 

 but more distinct, narrow, and clear cut. Duplin County, also in the Waccamaw 

 beds. South Carolina. 



Variety bella Conrad, s. s. In this, which (though not common, compared 

 with the other varieties) was the form figured by Conrad, to the other sculp- 



