Shell thin, small, about 15 mm. in length and depressedly conical. Base oval or ovate. Anterior slope straight, posterior slope convex. Apex a little in front of the middle. Orifice small, about 1 mm. long, circular in shape and situated slightly in front of the apex. Sculpture consists of 37 or 38 strong, radiating and widely separated ribs, between which there are alternated fine riblets. Concentric, separated laminae give a lattice-like appearance to the shell surface, forming nodules or scales where these laminae intercept the ribs. It is typically unicolored a milky white. Margin finely crenulated. Interior color polished white, the outside sculpture showing through in the form of radiating and concentric white lines. Internal callus of the orifice the same color as the rest of the inside: it is round, truncated and slightly excavated behind.

Diodora meta (Ihering, 1927) Meta Keyhole Limpet
Distribution: Florida, Texas; Brazil. Size: Approximately 15 mm.
Description: Color typically white, when fresh the interior of shell is a polished, glassy white; sculpture of distinct radiating, relatively widely spaced, large, round ribs alternating with smaller ribs; spiral ribs form nodules where they intersect spiral ribs, giving latticelike appearance; outer sculpture shows through on fresh shells; margin crenulate; orifice small and callused internally.
Habitat: On hard surfaces. In Texas found at Stetson Bank. Typically found at depths from 0 to 110 m (360 ft).
Remarks: This species is rare in Texas but has been collected in shallow water and in beach drift. See Ode (1988d).

Southern Florida (Dry Tortuga's) and Brasil.
This beautifully sculptured species is exceedingly rare. It occurs in shallow water, living apparently below the low-water line though occasionally washed up on the beaches. At this writing only the two extremes in its distribution are known, namely Florida and Brasil. Shallow water dredging in the West Indies and along the coasts of Central and northern South America should indicate its presence.