PLEIOCENE FOSSILS. 



PLATE XII. 



PECTENID M. 



Fig. 1. PECTEN PEEDEENSIS. Upper valve, natural size. Page 30. 



" 2. Lower valve. 



" 3. Side view of fossil. 



" 4. Outline of the form of the ribs. 



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



