Description by Nordsieck in German: Click german flag!

Acteon liostracoides: Shell small, translucent white, slender, with a blunt apex and nearly six whorls; surface polished, smooth except for microscopically fine spiral striae over the whole surface, stronger on the base; suture appressed, distinct, sides flatly compressed, the last whorl longer than the spire; aperture narrow, about two-thirds the length of the last whorl; outer lip sharp, thin, slightly arcuate, rounding evenly into the short slightly thickened arcuate pillar which carries an obscure fold; body without enamel. Height, 7; maximum diameter, 2.7 mm. U. S. Nat. Mus. Cat. No. 107917.
Off Fernandina, 15 specimens.
At first sight this shell might be mistaken for a Melanella. Its nearest relative seems to be A. nitidus Verrill, than which it is more slender, acute, and flat-sided.

Acteon propius: Shell small, white, rather slender, with a large bluntly immersed nucleus, distinct slightly shouldered suture and about five moderately convex whorls; sculpture of evident incremental lines and microscopically minute spiral striatum; aperture half as long as the shell, narrowly ovate, the pillar twisted but not distinctly plicate; base imperforate; length, 4.3; diameter, 1.7 mm. U. S. Nat. Mus. Cat. No. 107919.
Off Fernandina, two specimens.
This resembles A. nitidus but has the aperture longer in proportion to the total length, the suture slightly turrited and the spiral striation finer.

Mediterranean Sea and North Atlantic. Azores and in Caribic area.