30 PLEIOCENE FOSSILS. 



. PECTEN PEEDEENSIS.— (Neio Species.) 



Plate XII., Figs. 1, 2, 3, 4, 5. 



P. testa trigono-ovata, crassa, cequilaterali ; costis 8, ampliter nodosis, concentrice striatis, 

 sub-squamosis. 



Description. Shell triangularly ovate, somewhat flatly convex, equivalve, equilateral ; 

 with eight large knobbed ribs, the whole concentrically covered with squamose striae. 

 Lower valve with the ribs generally dislocated vertically, and rather abruptly on the 

 umbones. The interstices between the ribs become very wide towards the pallial margin. 

 The upper valve with ribs strongly knobbed. 



Of all the fossil Pectens this is the thickest and most robust. It was first observed by Mr. 

 Ruffin, on the Pee Dee, and the name is that by which he designated it. 



It is very closely related to, if not identical with P. nodosus, of the Gulf of Mexico. In 

 the recent shell, the whole surface is marked by strongly impressed radiating lines, whilst 

 in the fossil the surface is covered by radiating and transverse stride. 



Plate XII., Fig. 1. Upper valve, natural size. 



" 2. Lower valve. 



" 3. Side view of fossil. 



" 4. Outline of the form of the ribs at margin. 



" 5. Magnified view of a portion of a rib, showing the radiating and transverse striw. 



Locality. Darlington District. 



Museum, College of Charleston, S. C. 



