Cyclostremiscus pentagonus (Gabb, 1873) is a member of the microgastropod family Tornidae that grows to be up to 2.2 mm in size. The shell is flattened, compressed, but with the spire projecting in early whorls, sculpture of microscopic growth lines. The last whorl in cross-section has a pentagonal shape. Base with two main spiral ridges. Shell color whitish-translucent, clear. The shell illustrated was collected in 2008 by former Museum collection volunteer Lois Dunnam on the East End of Sanibel.
The Trilix Vitrinella, Cyclostremiscus pentagonus. Photos by James F. Kelly.