490 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.51. 



DESCRIPTIONS OF SPECIES. 



ARCA SUBPKOTRACTA Heilprin. 



Area subprotracta Heilprin, Proc. Acad. Nat. Sci., Phila. for 1881, p. 44SJ. 

 Area (Byssoarca) protracta Conrad, Journ. Acad. Nat. Sci., Phila., new ser., 

 vol. 1, 1848, p. 126, pi. 13, fig. 36; not of Rogers, 1837. 



Locality. — Station 6171, on the east bank of the FUnt River at 

 Bainbridge, Decatur County, Georgia, L. W. Stephenson, 1908. U. S. 

 Nat. Mus. Cat. No. 166762. Also in the Oligocene of Vicksburg, Mis- 

 sissippi; Conrad. 



BARBATIA (CALLOARCA) CUCULLOIDES Conrad. 



Area cueidloides Conrad, Fos. Tert. Form., No. 3, p. 37 (not figured), 1833. 

 Byssoarca lima Conrad, Journ. Acad. Nat. Sci., Phila., new ser,, vol. 1, 1848, 



p. 125, pi. 13, fig. 23; not of Reeve, 1844. 

 Barbatia (Calloarca) cuculloides Dall, Trans. Wagner Inst. Sci., Phila., vol. 3, 



1898, p. 624. 



Locality. — Station 3383, at the base of the bluff at Little Horseshoe 

 Bend, just below the mouth of Blue or RusseU Spring branch, on the 

 east bank of the FHnt River, 4 miles below Bainbridge, Decatur 

 County, Georgia, in fossil coral reef; T. W. Vaughan, 1900. U. S. Nat. 

 Mus. Cat. No. 166763. Also in the Oligocene of Vicksburg, Mississippi; 

 Com-ad. 



GLYCYMERIS COOKEI, new species. 



Plate 84, figs. 1, 2. 3, 4. 



SheU small, shghtly inequilateral, strongly sculptured; valves 

 thick, suborbicular, with inner margins fluted in consonance with the 

 external sculpture and the areas between the umbones very narrow 

 and relatively long; sculptm'e of 12-15 stout flattened radial ribs, 

 which distaUy become grooved on the summit and eventually duplex; 

 the interspaces are channeled and about as wide as the ribs; in some 

 specimens traces of intercalary threads, one to an interspace, begin 

 to show themselves. There is no perceptible concentric sculpture, 

 but all the specimens show a tendency to gi-anulation of the surface, 

 which, however, may be due to conditions of fossilization. The 

 umbones are small and pointed; the hinge line is narrow, with seven 

 or eight weU-developed teeth on either side of the center. Height, 

 14; breadth, 15; diameter (double), 10 mm. 



Locality. — Station 7095 on the east bank of Fhnt River, just above 

 Lambert Island, about 10^ miles below Bainbridge, Decatur County, 

 Georgia; also at station 7076, about half a mile below the island. 

 Cooke and Mansfield, 1914. U. S. Nat. Mus. Cat. No. 166710. 



The peculiar sculpture of this species is quite distinctive and does 

 not closely resemble any other known Oligocene species. It is quite 

 probable that it attains a larger size than that above noted. 



