INSTITUTE OF SCIENCE, PHILADELPHIA. 131 



SUPPLEMENT. 



ADDITIONAL SPECIES FROM THE PLIOCENE DEPOSITS OF THE 



CALOOSAHATCHIE. 



For the following new species of fossils I am indebted to Mr. Joseph 

 Willcox and Dr. W. H. Dall, by whom they were collected during 

 a recent visit to the region. 



Peoten pernodosus, nov. sp. Fig. 69. 



Shell nearly equivalve, strongly plicated and ribbed, the basal margin 

 of both valves incurved ; ribs about nine, broadly elevated, and pro- 

 foundly knobbed on both valves, those of the right valve almost through- 

 out broader than the interspaces, those of the left valve of equal width, 

 or narrower than the interspaces, and alternating in size; knobs closely 

 placed, more or less hollow, about ten on each rib in the largest speci- 

 men ; ribs and interspaces radiately ribbed or lined, the lines crossed by 

 numerous rugose creases of growth ; ears unequal, longitudinally lined 

 or grooved, the lines declivous ; cardinal pit moderately deep. 



Length, four inches ; height, from apex to basal margin, four inches. 



This beautiful scallop, which is, with little doubt, the immediate ances- 

 tor of the recent Pccten nodosus, can be readily distinguished from that 

 'species (and likewise from Pccten snbnodosits, which is hardly more than 

 a variety of P. nodosus) by the much greater prominence and regularity 

 of its closely packed knobs, and in the circumstance that both valves are 

 nearly equally knobbed. In Pecten nodosus the ribs of one valve, usually 

 the right, are largely destitute of true knobs, although exhibiting here 

 and there ephippial undulations; the knobs are also less regularly rounded, 

 and the radiating lines are less numerous. Much the same differences 

 separate the species from P. Peedcensis, from the Miocene of South 

 Carolina. 



Cardium Dalli, nov. sp. Fig. 70. 



Shell ovately elevated, moderately ventricose, with the beaks apical, 

 touching (or nearly so), and directed slightly backwards ; ribs about 30 

 to 33, smooth, moderately elevated, teretely rounded, with narrow, im- 

 pressed interspaces; the ribs on the posterior slope narrower and more 

 crowded than over the general surface, minutely echinated in part. 



Hinge-line narrow, acutely curved, with prominent lateral teeth; a 

 prominent triangular cardinal tooth in each valve. 



