PLEIOOENE FOSSILS. 97 



MACTRA SIMILIS. — Say. 



Plate XXIII. Fig. 8. 



Mactra similis, Say, Jour. Acad. Nat. Sci., Vol. 2, p. 309. 



M. testa oblong o-ovali cequilaterali, tenuissime et concentrice striata; lineis elevatis sub- 

 laminatis concentricis duabus vel tribus; umbonibus centralibus. 



Description. Shell oblong-oval equilateral, surface finely marked with concentric 

 lines of growth, which are almost obsolete, and always interrupted irregularly with two or 

 three raised sub-laminated concentric lines; buccal and anal margins nearly equally 

 rounded, the anal a little more pointed in some specimens; beaks central. 



This is a very abundant living species on the Southern coast, and somewhat resembles 

 in outline M. oblongata, but is easily distinguished, as the folds on the buccal end are 

 wanting; it is also a thicker shell than M. oblongata. 



Plate XXIII. Fig. 8, Natural size, 



Locality. Black River; Smith's, Goose Creek, 



Museum, College of Charleston. 



MACTRA LATERALIS. — Sat. 



Plate XXI II. Fig. 9. 



Mactra lateralis, Say, Jour. Acad. Nat. Sci., Vol. 2, p. 309. 

 Mactra lateralis, Con., Amn. Mar. Conch., p. 62, pi. 14, fig. 2, 



M. testa parva, sub-triangulari lavi vel interdum tenuiter striata, sub-cequilaterali; 

 margine buccali rotundata; margine anali elongata, acuta; regione buccali plana, cordata. 



Description. Shell small, sub-triangular, smooth, or finely marked by the lines of 

 growth, sub-equilateral; buccal margin rounded; anal margin prolonged, pointed; buccal 

 region flat, heart shaped. 



