TRANSACTIONS OF WAGNER 

 738 



TERTIARY FAUNA OF FLORIDA 



Pcctcn Deshayesii \2>x. /ir;/n/ s Gregorio, Claib. Mon., p. 181, pi. 21, fig. 15, 1890. 



? Pcctcn mmutus Lea, op. cit., p. 88, 1833. 



Not P. Dcs/iayesii "Hyst, Coq. et Polyp. Fos., p. 288, 1845. 



Jacksonian of St. Stephen's Bluff, Tombigbee River, Alabama, of Clai- 

 borne, Mississippi, and four miles west of Live Oak, Florida; Burns and 

 Stanton. 



This species is positively known to occur in the Jacksonian at Claiborne 

 and elsewhere, but I have obtained no specimens from the vast amount of 

 marl belonging to the true Claibornian sands horizon which has come under 

 my notice. 



The shell is rather variable, losing the concentric sculpture when worn. 

 It has fifteen to twenty-one ribs ; the byssal notch is inconspicuous ; in the 

 right valve the ribs are strong and rounded on top with the concentric sculp- 

 ture chiefly evident at their sides, the interspaces sparsely imbricated with one 

 or two interstitial divaricate threads near the base ; ears flattish, slightly scaly, 

 with radial grooves, notch very shallow; left valve with the sculpture like 

 that of P. wahtubbcaiius but much less dense. Altitude and latitude forty- 

 eight millimetres. There is hardly any room for doubt that Lea's other 

 species are merely the immature stages of this same shell. 



Pecten (Chlamys) cocoanus n. s. 

 Plate 34, Figure 23. 



Jacksonian Eocene of Red Bluff, Mississippi, and Cocoa Post-Office, 

 Choctaw County, Alabama; Burns. 



Shell small, thin, flattish, oblique, produced behind, with about twenty- 

 five small, low, entire ribs, rounded above, and about fourteen interstitial single 

 smaller threads, the tops of all of which are somewhat sparsely concentrically 

 imbricated, the interspaces showing only incremental lines ; ears quite unequal, 

 small, the posterior smaller, each with five or six low, hardly scaly radii ; 

 inside of the valve obsoletely channelled, the cardinal crura developed. Alt. 

 23, lat. 23 mm. 



This shell differs from P. vicinbranostis by its entire and less numerous 

 ribs, and from P. ivalitubbeaims by its greater obliquity, its entire, less con- 

 spicuous, and less densely imbricated ribs. 



Pecten (Chlamys) G-reggi Harris. 

 PccteH Greggi iizms, Bull. Pal., i.\., p. 45, pi. vii., figs. 4-5, 1897. 



