70 AMERICAN JOURNAL 



Melampus longidens, Conrad. — Proceed. Acad. Nat. Sciences, 

 1862, p. 584. 



Locality. — Yorktown, Virginia. 



I had referred this shell to a new subgenus, Ensiphorus, as 

 it has only the one large fold, but it is, more probably, a true 

 Tifata, although that genus has two colurnellar folds. 



SAXICAVITLE. 

 SAXICAVA, Bellevue. 

 S. parilis, Conrad. — PL 4, fig. 6. 



Description. — Sub-oval, ventricose, equilateral, very thin in 

 substance, end margins nearly equally rounded, summit 

 prominent, lines of growth minute. 



Locality. — Shiloh, N. J. 



ANATINID^E. 

 PERIPLOMA, Schum. 

 P. alta, Conrad.— PI. 4, fig. 10. 



Description. — Obtusely ovate in the adult, substance thin; 

 sub-orbicular when young; posteriorly ventricose; anterior 

 side sub-rostrated, compressed; the end truncated, direct, much 

 above the basal line, which is profoundly rounded ; anterior 

 submargin of the right valve with a slightly raised line, ante- 

 rior to which the valves are suddenly contracted. 



Locality. — -Shiloh, Cumberland Co., N. J. 



This large species is abundant, but always more or less dis- 

 torted in the adult specimens, so that the large figure is only 

 approximate, but the young appears to have its original form, 

 as given in the figure. It is allied to the very small species 

 of the Southern coast, P. papyratia (Anatina), Say, which is 

 represented in fig. 9 for comparison, and is the only figure yet 

 published of that recent species. P. alta is unknown in any 

 other locality than Shiloh. 



THRACIA, Leach. 

 T. my.eformis, Conrad. — PI. 4, fig. 3. 



Description. — Ovate, inequilateral; posterior side somewhat 

 produced, compressed, much reflexed ; the end acutely 

 rounded. 



Saxicava myseformis, Conrad. — Proceed. Acad. Nat. Sciences, 

 1862, p. 585. 



Locality. — With the preceding. 



