Notes on the Fauna of the Chipola Formation-XXXV A New Species of the Genus Modulus (Mollusca: Gastropoda)

Abstract

The genus Modulus has existed in America since the Cretaceous Period (Dall, 1892, p. 293).  Recent adult specimens living in the Atlantic  re small, with widths ranging from 9 to 16 mm and heights of 9 to 17 mm (Abbott, 1944;  Petuch, 1987).  Keen (1971) lists three species living in tropical west America.  Like their Atlantic counterparts, they are small gastropods with widths of 15 to 17 mm and heights of 12 to 17 mm.