Puperita pupa is represented by the striped shell in the center of the photo. (Also in the photo is Echinolittorina mespillum, the multiple brown shells, found here: http://www.inaturalist.org/observations/6321654.)

Echinolittorina mespillum is represented by the multiple brown shells in the photo. (Also in the photo is Puperita pupa, the striped shell in the center, found here: http://www.inaturalist.org/observations/6315160.)