Shell size to 25 mm; shell limpet-like, tall, with oval outline. Sculpture of poorly defined radial lines. Inside with asymmetrical distribution of muscle scars. Scar of mantle attachment with gap on right side. Color of fine, alternating radial lines of black and white; these lines visible also on inner edge of shell. Lives on rocks or other hard substrates. Minute eggs (arrow) are laid in gelatinous strands found adhering to rocks in Spring. Specimen with eggs photographed on jetty between Sanibel and Captiva.