PLEIOCENE FOSSILS. 87 



This fossil we refer, with hesitation, to V. permagna, Con., a species which he has 

 named but not described; at least we have not been so fortunate as to find any such 

 description. It was originally referred by him to V. Mortoni, a species which is fossil in 

 the Post Pleiocene and recent on the coast. From this it is at once separated by its less 

 prominent and less recurved beaks, by its somewhat lanceolate lunule, by being less 

 inflated and differing altogether in outline. V. permagna has the anal side regularly 

 arcuated, and two obscure folds extend to the thick and somewhat lamellar lip. The out- 

 line of the shell is remarkable for its regularly ovate form. The shell is covered with 

 closely arranged lines of growth. The margin is smooth, and if this be a constant and 

 not an accidental character, it may serve to distinguish this species from all the large 

 Venerid^e. 



V. permagna resembles V. Rileyi more nearly than any other species. Like the latter, 

 it is very inequivalve, but differs from it chiefly in the less prolonged anal side and in its 

 neatly oval outline. 



Plate XXII. Fig. 2, Natural size. 



Locality. Waccamaw. * Museum, College of Charleston, 



PETIUCOLA.—Lam. 



PETRI. COLA P H L A D I F R M I S . — L a m. 



Plate XXI. Fig. 5. 



Petricola pholadiformis, Lam., An. sans Ver., 3rd Ed., Brux., Vol. 2, p. 554 



Petricola pholadiformis, Gould, Inver. Mass., p. 63. 



Petricola fornicata, Say, Jour. Acad. Nat. Sci., Vol. 2, p. 319. 



P. testa elongata, cylindrica; latere buccali brevissimo, radiato, costato et striato; costis 

 lamellosis; latere anali elongato, striato, lunula ovata. 



Description. Shell elongated, cylindrical, buccal side very short, radiately and striate; 

 ribs lamellar; anal side much elongated, radiately striate; lunule ovate. 



This species bears some resemblance to Pholas costata, both in the form of the shell, 

 23 



