False Limpets of the Siphonariidae Family, as the name implies, resemble the True Limpets in appearance. They have asymmetrical profiles that are round or oval. The most notable difference between the two is that the False Limpets are air breathing as they lack the gill structures that most other mollusks have. Instead, they have either a mantle cavity that functions like gills and lungs, or they have secondary gills located within the mantle cavity. False Limpet Shells are easily identified in that they have a special respiration canal on the interior that runs to the margin. This canal allows the live snail to clamp down tightly on hard substrate and still circulate air into the mantle cavity. Like True Limpets, False Limpets have a wide, low, cone-like shape but they do not have a spiral. The apex is often eroded and the exterior of the shells s may be smooth or radially ridged with the ridges extending to the margins in many shells affording the shell with a scalloped edge.

False Limpets are found on rocks and other hard surfaces. They are found globally, with the exception of the North Atlantic, in tropical and temperate waters and are limited to the intertidal region. Their diets consist almost exclusively on microscopic algae. In turn they are preyed upon by crabs, fish, and predatory mollusks. There are between 75 and 195 species in the Siphonariidae Family or which five are found in coastal waters along the Baja.