TRANSACTIONS OF WAGNER 

 642 



TERTIARY FAUNA OF FLORIDA 



which are smooth and almost rounded ; those on the middle of the valve are 

 squarish, with wider channelled interspaces, and rippled or furnished with 

 transverse nodulation above, which grows stronger and more crowded ante- 

 riorly ; the ribs are not sulcate or dichotomous, and hardly differ on the two 

 valves; hinge-line straight, rather long, and with conspicuous angles at the 

 ends ; anterior end of the valve rounded, base nearly parallel with the hinge- 

 line, posterior end somewhat produced ; beaks narrow, cardinal area with 

 from three to five sets of lozenge-shaped groovings ; hinge strong, the teeth 

 in two adjacent series, somewhat oblique, smaller mesially, at the anterior end 

 of the hinge sometimes more or less broken into granules; inner margin of 

 the valves fluted, interior radially striate. Lon. of a large valve 47, alt. 37 

 mm.; lon. of figured shell 39, alt. 30, diam. 28 mm. 



This species differs from A. santarosana, which occurs in the same beds, 

 by its more rhombic form, proportionately longer hinge-line, and unsulcate 

 ribs. It is also a larger and less elegantly sculptured shell. A. staininea 

 Say, of which staininata may prove to be an Oligocene race, has a proportion- 

 ately longer hinge-line, is more sharply truncate behind, and more obliquely 

 rounded in front, the beaks are less elevated and wider, the ribs anteriorly are 

 only sparsely and feebly nodular, while the aspect of the whole shell is less 

 elegant. 



Scapharca (Scapharca) staminea Say. 



Area staininea Say, Am. Conch., iv., pi. 36, fig. 2, 1832. 



Area elevata Conrad, Fos. Med. Teit., No. i, cover, 1840. 



Area triquetra Conrad, Proc. Acad. Nat. Sci. Phila., i., p. 305, 1843 ; Fos. Med. Tert., 



p. 59, pi. 31, fig. 2, 1845. 

 Scapharea triquetra Conrad, Proc. Acad. Nat. Sci. Phila. for 1862, p. 580, 1863. 



Miocene of Calvert Cliffs, Choptank River, and Jones's Wharf, near Cen- 

 treville, Maryland; of York River, Virginia, and Walton County, Florida; 

 Say, Burns, Harris, and Johnson. 



The differences between this and A. staniiiiata are detailed under that 

 species. 



Scapharca (Scapharca) chiriquiensis Gabb. 

 A. chiriquie7isis Gabb, Proc. Acad. Nat. Sci. Phila., xii., p. 567, 1861. 



Oligocene of Chiriqui, Central America, and of an island in Lake Henri- 

 quillo, St. Domingo; Gabb and Rowell. 



Tiie absurdity of referring this species to A. grandis Broderip is evident 

 on a comparison, and the A. patricia of Sowerby (Quart. Journ. Geol. Soc. 



