TRANSACTIONS OF WAGNER 

 8l6 



TERTIARY FAUNA OF FLORIDA 



Subgenus BARNEA s. s. 



Shell with only one accessory plate (protoplax) ; anterior gape small. 

 Type Pholas Candida Linne. 



Subgenus SCOBINA Bayle, 1880. 



Shell with a transverse mesoplax and a lanceolate protoplax. Type 



P. costata Linne. 



Barnea (Scobina) costata Linne. 

 Pholas costatus Linne, Syst. Nat., Ed. x., p. 669, 1758 ; Lam., An. s. Vert., v., p. 445, 



1818 ; Sby., Gen., No. 23, pi. i, 1824 ; Holmes, Post-Plcioc. Fos. S. Car., p. 58, pi. 

 9, figs. I, I a, 1858; Tryon, Mon. Pholad., p. 73, 1862. 

 Pholas virginianus Lister, Hist. Conch., Ed. ii., pi. 5, fig. 434, 1770. 



Pliocene of the Caloosahatchie marls, Florida, Dall ; Pleistocene of Mas- 

 sachusetts, at New Bedford; of Maryland, at Cornfield Harbor; of South 

 Carolina, at Simmons Bluff; of Florida, at Osprey ; recent from Massachu- 

 setts south to Mexico and Brazil. 



The recent shell is identical with that of the Pliocene, but differs from 

 the Miocene form by its uniformly thinner texture, resulting in a sort of 

 punctate pattern on the interior of the valves, its larger size, and the different 

 proportions of its umbonal reflection, much as P. canipcchiensis differs from 

 the Miocene P. producta. 



Barnea (Scobina) arcuata Conrad. 

 Pholas arcuata Conr., Medial Tert., cover of No. 2, p. 3, 1841 ; Proc. Acad. Nat. Sci. 



Phila. for 1862, p. 571, 1863. 



Pholas aciiininata Conr., Medial Tert., p. 77, pi. 44, fig. 2, 1845. 

 Pholas costata Tuomey and Holmes, Pleioc. Fos. S. Car., p. 102, pi. 24, fig. 4, 1857 ; 



not of Linne. 



Miocene of Nansemond River, near Suffolk, Virginia, Burns; of Mary- 

 land, Conrad ; of South Carolina, in the Waccamaw district, Tuomey. 



This species is known from B. costata by its longer umbonal reflection 

 and smaller size. It is usually more solid and thick, with more numerous 

 and finer radial ribs. Fragments from the Galveston arlesian well may be- 

 long to it, but have not been accessible to me for critical comparison with 



B. costata. 



Barnea truncata Say. 



Pholas tmncaia Say, Journ. Acad. Nat. Sci. Phila., ii., p. 321, 1822 ; Sby., Thes. Conch., 

 i., p. 488, pi. 104, figs. 29, 30, 1849; De Kay, Zool. N. Y., Moll., p. 248, pi. 34, 

 fig. 323 a-b, 1843 ; Holmes, Post-Pleioc. Fos. S. Car., p. 57, pi. 9, fig. 4, 1858. 



Pholas (Cyrtoplcuni) truncata Tryon, Mon. Pholad., p. 74, 1862; Cat. Pholadacea, p. 

 2, 1867. 



