Described as Collisella (which is synonymous)
Shell. Apex typically subcentral; exterior sculpture of concentric growth lines, radial riblets, radial ribs, or nodules. Exterior color pattern variegated; interior margin and central area usually colored; intermediate area usually not colored. Animal. Lacks secondary gill; oral lappets typically lacking. Radula. Lateral teeth generally unequal in size and shape; single pair of reduced marginal teeth (uncini) present at posterior end of ribbon segment. Morphology and arrangement of lateral plates complex. HABITAT High intertidal to subtidal (approximately 50 m); generally eurytopic, several specialist species associated with algal substrates or epizooic on other molluscs.

Until recently, Lottia was considered by most workers to be a monotypic genus. However, recent work by Lindberg and McLean (1981) has shown that acmaeids with secondary gills are found in 2 different shell structure groups. Thus, Lottia was redefined to include those species with a secondary gill and a simple prismatic outer shell layer, while Scurria Gray, 1847, was defined to include those acmaeids with a secondary gill and a complex prismatic outer shell layer.