The name "fenestrata" refers to the checkerboard pattern of white and brown that is seen around the exterior margin of at least some of these limpets. Morris (1966) acknowledges the wide diversity of coloration within this species by recognizing two subspecies: A. fenestrata fenestrata, which is grayish green with flecks of pale yellowish. Its inside is bluish white with a narrow brown inside border. A. fenestrata cribraria, the northern form, is dark within the shell (almost solid brown). There are many intergrades where the two forms meet (central CA).