TRANSACTIONS OF WAGNER 

 682 



TERTIARY FAUNA OF FLORIDA 



Pliocene of Peace Creek, near Arcadia, and Alligator Creek, Florida. 



The original figure of Conrad is very poor. The species is widespread 

 and recognized by its flat upper valve, few-ribbed lower valve, straight hinge- 

 line, flat hinge-area, with excavated central channel and the peculiar vermicular 

 sculpture of the submargin on each side near the hinge-line. It is not im- 

 probable that O. pcrcrassa Conrad is a peculiar local race of this species and 

 that 0. Mortoni Gabb and 0. vicksfatrgensis Conrad are young pebble-grown 

 shells of the same species as the large, well-grown specimens which I regard 

 as normal trigonalis. The differences are, however, so marked that it is 

 probably best to keep them separate for the present, until more is known. 

 0. subtrigonalis of Evans and Shumard is a Cretaceous species. Varieties of 

 0. coinpressirostra approach very closely to this species. 



Ostrea vicksburgensis Conrad. 

 O. vicksburgensis Conrad, Proc. Acad. Nat. Sci. Phila., iii., p. 296, 1848 ; Journ. Arad. 



Nat. Sci., 2d Ser., i., p. 126. pi. 13, figs. 5, 37, 1848. 

 O. panda Morton, Syn. Org. Rem., p. 51 (ex pcerte), pi. 19, fig. 10, 1834. 

 O. Mortoni Gabb, Proc. Acad. Nat. Sci. Phila., p. 329, 1861. 



Jacksonian Eocene of Fail Post-Office and Cocoa Post-Office, Choctaw 

 County, Alabama; Eocene of South Carolina and Clarksville, Alabama; 

 Vicksburgian Oligocene of Vicksburg, Mississippi ; Burns and Johnson. 



As previously noted, this species is probably an offshoot of 0. trigonalis. 

 The Vicksburg type differs from the Jacksonian only in having the ribs less 

 imbricated and more rounded, a distinction which is not constant. 



Ostrea falco Dall. 

 PLATE 30, FIGURES 4, n. 

 O. falco Dall, Proc. U. S. Nat. Mus., xviii., p. 22, 1895. 



Jacksonian Eocene of Cocoa Post-Office, Choctaw County, Alabama, in 

 the Zeuglodon bed ; Burns and Schuchert. 



This remarkably distinct species is well characterized by its cellular lower 

 valve, radiately striate, flat, arcuate, and hooked upper valve, and the strong 

 denticulations of the submargin. Held horizontally, the profile of the upper 

 valve is remarkably like that of the head of a raptorial bird, and this form is 

 exceptionally constant. 



Ostrea podagrina Dall. 



PLATK 30, KICUKES 5, t>. 

 O. podagrina Dall, Proc. U. S. Nat. Mus., xviii., p. 22, 1895. 



