Among the species in the genus Atlanta, this attains the largest size (to 10 mm shell diameter). It is also the type species in the genus. Shell flat, with a small, low spire of about 3 and 1/2 whorls. Full-grown shells with up to 6 whorls. Keel moderately elevated, rounded in profile, with a brown base in larger specimens. Shell walls strong, relatively thick. Shells are colorless, except in larger specimens that are faintly yellowish. Eyes relatively small. Radula large, with high lateral teeth; number of tooth rows limited (to about 60). Distinctive sexual dimorphism in the radula. In adult males marginal teeth are sharply-bent hooks, much shorter than the respective lateral teeth. In females marginal teeth are longer and less sharply curved.
This species has been confused with other species in the past due to the absence of distinctive shell characters; e.g., comparability of shell shape, absence of surface sculpture, and spires not notably elevated or inclined (Richter, 1993). These problems are understandable when, as is generally the case, one has only juveniles and young adults to work with. Species having shells similar in general appearance to Atlanta peroni include Atlanta fragilis, Atlanta rosea and Atlanta gaudichaudi in the Atlantic, and Atlanta frontieri and Atlanta plana in the Indo-Pacific. Although Atlanta peroni is quite common in the Atlantic, it is rare in the Indian Ocean, where the related species Atlanta frontieri is abundant (Richter, 1993).
See the family Atlantidae for a discussion of the species groups.