NO. 2162. FLINT RIVER OLIGOCENE FOSSILS— DALL. 495 



This shell seems to find a place halfway between Crenella and 

 Botula. The tyj^e is A. filosa Conrad, from the Vicksburgian, from 

 which the present shell differs by its much less prominent umbones 

 and dorsally less and ventrally more arcuate profile. 



LITHOPHAGA NUDA Dall. 



Lithophaga nuda Dall, Trans. Wagner Inst. Sci. Phila., vol. 3, 1898, pt. 4, p. 

 800, pi. 11, fig. 7; pi. 35, fig. 27; Bull. U. S. Nat. Mus. No. 90, 1915, p. 129, 

 pi. 24, fig. 4; pi. 26, fig. 7. 



Locality. — Station 3381, at the base of the bluff at Little Horseshoe 

 Bend, just below the mouth of Blue (or Russell) Spring branch of the 

 Flint River, 4 miles below Bainbridge, Decatur County, Georgia; T. 

 W. Vaughan, 1900. U. S. Nat. Mus. Cat. No. 166755. Also from 

 the Ortiiaulax pugnax zone at Ballast Point, Tampa Bay, Florida. 

 U. S. Nat. Mus. Cat. No. 165187. 



The shell is seldom well preserved, but the casts of the burrows of 

 this species are very common, and often in their sihcified form retain 

 a cavity more or less occupied by water. 



CRASSATELLITES PARAMESUS, new species. 



Plate 85, figs. 4, 5, 7, 8. 



Shell solid, thick, inequilateral, the anterior end shorter; sub- 

 ovate, beaks small, pointed, flattened; anterior dorsal margin with 

 an ovate-lanceolate, nearly smooth, deeply depressed lunule, the 

 outer margin of which is abrupt and sharp-edged; the escutcheon is 

 more than twice as long as the lunule, less depressed, concentrically 

 striated, and with the bounding carina rounded off and less abrupt; 

 the hinge is strongly developed, the anterior cardinal tooth very 

 prominent, arcuately produced; the resihary pit narrow and deep; 

 there are no traces of lateral teeth, though the dorsal margins of the 

 right valve are attenuated and produced; the inner margins of the 

 valves are not crenulated; the adductor scars are conspicuous, the 

 posterior larger, both rounded; the external sculpture on the flat- 

 tened beaks comprises about ten concentric low rather sharp waves 

 with much wider interspaces, angulated behind where they cross a 

 low ridge which radiates from the viomity of the umbo to the pos- 

 terior basal margin, near which it becomes obsolete; in front of this 

 ridge the concentric waves become closer, smaller, and more numer- 

 ous, behind it every alternate rib, in general, ceases and the inter- 

 spaces between the others are therefore about twice as wide as on the 

 anterior part of the valve; the basal margin is obscurely angulated 

 by the end of the ridge and the margin behind it sub truncated; the 

 anterior end is evenly rounded and the base gently arcuated. Height 

 28; length of sheU 35; of part behind the vertical from the umbones 

 21; diameter 16 mm. 



