364 AMERICAN JOURNAL 



NATICA, Lamarck. 



Natica erecta. — t. 27, f. 11. 



Description. — Shell subglobose; spire elevated; volutions 

 five, ventricose; suture well marked; substance of the shell 

 thin; aperture large, obliquely ovate; outer lip thin and 

 sharp ; columellar lip slightly thickened and grooved, without 

 callus; umbilicus small, partly concealed by an extension of 

 the columellar lip ; surface of the shell polished. 



Localities. — Six miles above Claiborne, on the west side of 

 the river ; and ten miles below Prairie Bluff, Alabama. 



Natica peespecta. 



Description. — Shell oblique, of medium size; substance 

 thick; volutions four in the largest individuals, very ventri- 

 cose ; spire low ; suture very distinctly channelled ; umbilicus 

 proportionally large, entirely destitute of a callus, the volu- 

 tions being distinctly visible to the apical one ; aperture semi- 

 lunate, the inner lip spreading somewhat on the preceding 

 volution, opposite the umbilicus it is thin and emarginate; 

 outer lip sharp ; surface polished. 



This beautiful little shell differs from any described species, 

 in the deep channelling of the suture and the characters of 

 the umbilicus. 



Locality. — Nine miles below Prairie Bluff, Alabama. 

 Natica reversa. 



Description. — Shell small, globose; spire moderately ele- 

 vated ; volutions ventricose ; suture deep ; aperture semicircu- 

 lar, and moderately large, equaling two-thirds the length of 

 the shell; outer lip sharp; inner lip slightly thickened, spread- 

 ing over the preceding volution; callus represented by a 

 thickened spiral ridge, deposited on the left side of the um- 

 bilicus, and uniting with the peristome at the inner basal 

 angle; substance of the shell thick; surface polished. 



Dimensions. — Height 'Z inch. 



Locality. — Nine miles below Prairie Bluff, Alabama. 



Natica (Polinices) onusta. 



Description. — Shell obliquely elliptical; spire low, a very 

 small portion only of the inner volutions showing; volutions 

 flattened in the upper part, and abruptly rounded below; su- 

 ture slightly channelled ; aperture very large, obliquely semi- 

 lunate; callus very large, entirely filling the umbilical portion 

 of the shell; surface smooth, or marked only by fine lines of 

 growth. 



