(Watson, 1886) 
Scissurella alta Watson, 1886 (original combination)
The shell grows to a length of 2.5 mm. The thin, white shell has a globose shape. It is transparent and strongly sculptured. It has a tumid base, a small umbilical chink. It has a short subscalar spire (on which the old canal slit forms the edge of the successive whorls), and a smallish somewhat prominent rounded tip. Its sculpture shows frequent, strongish, rounded, longitudinals. The curved riblets radiate out from the sutures. They are of much the same strength on the base as above. The spirals are located at about one-third of its height from the suture. The body whorl is somewhat feebly carinated by the old canal scar, which is depressed and finely scored across between the narrow slightly projecting edges of the lip. On the upper surface a few very obsolete spirals may be seen. The whole base is reticulated by spiral threads, which are closer set, but almost as strong as the radiating riblets. The conical spire is rather depressed and rises regularly to the extreme tip. The apex is round and prominent. The five whorls are flat and sloping above. They are carinated below the carina towards the mouth slightly openly constricted and then tumid on the base.The suture is impressed. The aperture is round. The outer lip is freely curved. The thin inner lip is concave at the base of the columella, straight, rounded, and very much expanded on the columella with an angulated and very patulous junction to the outer lip in front. There is a small umbilical furrow and chink half hidden behind it. (original description by Watson) 
- Watson, R. B. 1886. Report on the Scaphopoda and Gasteropoda collected by H.M.S. Challenger during the years 1873-1876. Report on the Scientific Results of the Voyage of H.M.S. Challenger, Zoology 15(2): i-v, 1-680, 692-756, 50 pls. Her Majesty's Government: London.
- Anatoma alta (Watson, 1886). Retrieved through: World Register of Marine Species on 11 April 2010.
- G.W. Tryon (1890), Manual of Conchology vol. XII
- Rosenberg, G., F. Moretzsohn, and E. F. García. 2009. Gastropoda (Mollusca) of the Gulf of Mexico, Pp. 579–699 in Felder, D.L. and D.K. Camp (eds.), Gulf of Mexico–Origins, Waters, and Biota. Biodiversity. Texas A&M Press, College Station, Texas.