Shells mediul-sized to large, thin-walled, subglobular, with a small spire and an inflated last whorl. Sculpture made up of large spiral costae. No operculum at adult stage.
 

Shell medium-sized, « subglobose, imperforate, and sculptured with strong spiral ridges. Axial sculpture absent or consisting of fine axial ribs. Shell rather thin though strong. Parietal shield slightly to well-developed. Aperture large, outer lip reflected. Periostracum deciduous, thin and light straw-yellow in color. Embryonic whorls rather large, smooth… » – R. D. Turner: “The family Tonnidae in the Western Atlantic”, Johnsonia vol.II num.26, Cambridge 1948, p.178.
 

« Shell medium to very large in size, in shape from oval to globose, rather thin but strong and generally sculptured with strong spiral ridges. Axial sculpture consisting only of fine growth lines except on the early post-embryonic whorls where a minor reticulated sculpture is apparent in certain species. Parietal shield slightly, to well-developed and reflected over the umbilicus. Aperture large, with or without a reflected lip. Columella nearly straight or moderately twisted. Anal canal inconspicuous, siphonal canal short and broad. Periostracum thin, straw-yellow and deciduous. Embryonic whorls persistent, covered with a horny periostracum and devoid of sculpture » – R. D. Turner: op. cit. p.169.