TRANSACTIONS OF WAGNER 



7-J2 



TERTIARY FAUNA OF FLORIDA 



Pet-ten (P.-ii-iii/ir/iutssiinii) argenteus Marrat, Argo ExpecL, p. 7, 1876 ; not pf Reeve. (An 



immature specimen.) 

 Peeten sukatus Krebs, W. I. Mar. Shells, p. 134 ; not of Lam. 



Pliocene and Pleistocene of the Antillean region ; living in Cuba, Guade- 

 lupe, the Bahamas, and the Florida Keys. 



This species is often destitute of the nodosities, and in that condition is 

 referable to Chlainys. The very young shell is thin and glistening, in which 

 state it has been mistaken for the Chinese P. argcntcus Reeve. Old and worn 

 specimens have been taken for P. sulcatus Lam. Its analogue and precursor 

 in the Antillean Oligocene is the P. anguillcnsis Guppy. 



Pecten ( ^Jquipecten) perplanus Morton. 



J't-cten sp. Lesueur, Walnut Hills Fos., pi. 5, fig. 2, 1829. 



Pecten perplanus Morton, Am. Journ. Sci., xxiii., p. 293, 1833 ; Org. Rem., p. 58, pi. 5, 



fig. 5, and pi. 15, fig. 8, 1834. 

 Pecten Spillmani Gabb, Journ. Acacl. Nat. Sci., 2cl Ser., iv., p. 402, pi. 68, fig. 3, 1860. 



Eocene of St. Stephen's, Alabama, Morton ; of the Jacksonian at Jack- 

 son, at Turk's Cave, Cocoa Post-Office, Choctaw County, and Fair Post-Office, 

 near Claiborne, Alabama; at Pachula Creek and Shubuta, Clarke County, 

 Mississippi; in the Vickburgian or Lower Oligocene, near Gainesville, Alachua 

 County, at various localities in Levy County, and in the Nummulitic horizon 

 at Ocala, Florida, Ball, Burns, and Johnson ; Grant Parish, Louisiana, Johnson. 



Shell with twenty-three to twenty-five subangular ribs with sloping sides 

 and equally wide shallow interspaces, an obsolete thread on each side of the 

 median keel of each rib, stronger on the side away from the middle of the 

 valve ; in large ones another thread begins near the basal margin ; whole shell 

 covered by regularly spaced low, thin concentric lamella;, not crowded, which 

 are slightly produced as a little linguiform process over each rib and thread, 

 more prominent on the right valve, which has rather small, short ears, with 

 three to five spinose or imbricate radii, and a conspicuous but not deep byssal 

 notch ; left valve with sharper keels, feebler concentric lamellae, subequal ears, 

 with five or six low beaded radii ; shell plump in both valves, internal margin 

 strongly fluted ; hinge with the cardinal crura strongly developed and cross- 

 striated. Alt. 34, lat. 35 mm. 



A full description is given, as I have found this shell much confused in 

 nearly all the collections with P. Poulsoui, P. niipcms, and others. The types 

 of P. perplanus and P. Spillmani have been compared and their identity fully 



