MONOGRAPH 
OF THE 
GENUS: ANCULOTUS OF SAY. 
ANCULOTUS. 
GENERIC CHARACTER. 
Shell suboval, rarely conical; spire generally de- 
pressed; aperture suborbicular or obovate, rounded 
at base; base of the columella rounded or obtusely 
angulated; columella wide, thickened, polished, gene- 
rally with a callus near its superior junction with the 
labrum. 
OBSERVATIONS. 
Mr. Say,with his usual discrimination, has separat- 
ed this natural group ofshells from the genus Melania, 
from which they differ in their obtusely rounded base, 
and generally by their depressed form, several spe- 

