Stromboidea

• Aporrhaidae
  • Drepanochilus
    • Drepanochilus pusillus (Stanton, 1921)

Original Description of Anchura (Drepanochilus) americana var. pusilla by Stanton, 1921, p. 38:

• "Shell small, fusiform, consisting of about seven volutions; spire about equal to length of aperture and canal, with rounded volutions; last whorl with a strong carina above the middle and two successively smaller carinae below, the lower of which is sometimes obsolescent; anterior canal short and straight; expanded outer lip with a pointed, slightly upturned process that bears the continuation of the main upper carina to its end, above which the margin is concave, while below it forms a very gentle sigmoid curve or is almost straight to the end of the canal; no posterior canal, though the winglike outer lip extends upward and is applied to part of the penultimate whorl; inner lip moderately thick and connected above with the outer lip; surface marked by numerous small curved ribs crossed by fine, threadlike spiral lines, there being 25 or more of the ribs and from 13 to 17 of the lines visible on each of the larger whorls of the spire. On the last whorl the ribs are gradually reduced to tubercles on the principal carina and the spiral lines are increased by the intercalation of smaller ones until on the outer part of the wing there are about 10 above the upper carina, 6 between that and the middle carina, 4 between the middle and lower carinae, and about 15 below the lower carina."
• "Height, 11.5 millimeters; breadth of last whorl exclusive of wing, 5 millimeters; apical angle, about 30°."
• "Locality and position: The figured types with numerous other specimens were collected near Grand River post office in sec. 12, T. 22 N., R. 12 E., S. Dak. The species has also been collected 9 miles east, 8 miles southeast, and 7 miles southwest of Lemmon, S.Dak.; a quarter of a mile east of Bloom, S. Dak.; 7 miles south of Leith, 12 miles south and 19 miles southwest of Almont, and 6 miles north- west of Solen, N. Dak., all in the Cannonball marine member of the Lance formation."

Anchura (Drepanochilus) americana var. pusilla Stanton, 1921, pl. 6, figs. 14, 15

References

• Sohl, N.F. (1967). Upper Cretaceous Gastropods from the Pierre Shale at Red Bird, Wyoming. United States Geological Survey Professional Paper. 393-B, 1-46, pls. 1-11.
• Stanton, T.W. 1921. The Fauna of the Cannonball marine member of the Lance Formation; U.S. Geol. Survey Prof. Paper 128-A: 1-60, pls. 1-9