Variation in the Genus Orthaulax (Mollusca: Gastropoda)

Abstract

A study of approximately 750 specimens of Orthaulax gabbi Dall, from the Chipola Formation of northwestern Florida, reveals a high degree of variation in the spire height, spire angle, and nature of the cross-sectional outline of the shell. As these characteristics are the criteria upon which new species have been distinguished in the past it is probable that several of the existing taxa, if adequately known, would be found to be synonyms. The eleven described species of Orthaulax are listed with their stratigraphic occurrence. In addition, O. gabbi is discussed in greater detail and the color pattern of the species is figured.