22 FOSSILS FROM SOUTHERN UNITED STATES— BALL. vol.xviii. 



adductor scar; tlie minute sealed byssal foramen, under the middle of 

 the chondropliore, connected by a soldered linear suture with tlie upper 

 anterior margin of the valve; chondrox)hore rounded, triangular, broad, 

 radiately rugose above, recurved as a thin himina from the umbo in 

 fully adult specimens, rather closely sessile, and fitting into the umbonal 

 cavity of the left valve; left valve, with the ligamentary attachment 

 broadly triangular, marginated by a thin shelly lamina on each side, 

 and arched over by the elevated portion of the cardinal area; there is 

 no trace of a byssal-muscle scar in adult examples. Breadth in either 

 direction about 110; maximum diameter of the closed valves, 9 mm. 



Sopchoppy limestone, on the banks of Deep Creek, near the Sop- 

 choppy River, Wakulla County, Florida, collected by the U. S. Geo- 

 logical Survey. 



The original C'aroUais from the Eocene of Egypt; the present species 

 from the older Miocene of the Gulf border. 



OSTREA PODAGRINA, new species. 



Shell compact, thick and heavy, wider than high, with very short 

 wide beaks, coarsely imbricated surface, inflated shell, with three or 

 four strong, wide, rather irregular radial plications ; interior smooth, 

 distinctly marginated, with a large subcentral adductor scar; hinge 

 and beak flat, the ligamentary area in the flat valve hardly excavated, 

 the edges of the flat valve near the cardinal border with two obscurely 

 wrinkled projecting crura, which fit into shallow depressions in the 

 opposite valve; elsewhere there are no strite or pustules on the edge of 

 the valves. Height, 110; width, 100; diameter, 50 mm. 



West bank of the Suwanee River, Florida, at station 2G12, in the 

 ujiperniost Eocene bed. 



OSTREA FALCO, new species. 



Shell thin, the fixed valve thin, irregular, cellular or deep, adherent 

 over most of its surfiice, having a deep umbonal cavity under the car- 

 dinal border; the exterior rude, not perceptibly sculptured; free valve 

 flat, thin, with a very acute, usually curved, flat beak; the interior mar- 

 gins with a row of strong pustules extending two-thirds the length of 

 valve from the beak, and fitting into corresponding pits in the fixed 

 valve; adductor scar small, rather laterally situated; the valve as a 

 whole more or less arcuate; exterior showing remains of a purplish 

 tint, with low, numerous, even, concentric imbrications, each of which 

 is finely radially threaded, with rather wider interspaces between the 

 threads; general outline flabelliform, wide, and rounded in front and 

 acutely pointed behind. Height of a medium-sized specimen, 52; 

 width, 35; diameter, about 19 mm., but very irregular in different 

 specimens. 



Jackson Eocene, in the Zeuglodon bed, near Cocoa post-oftice, south- 

 ern Alabama, collected by Messrs. Burns and Schuchert. 



T^ije.— No. 129972. U. S. N. M. 



