The conoid shell of stipe dwellers is lower than on frond dwellers because the skirt of adult growth flares out laterally (1). At GS5 the adult skirt, extending all around the shell, forms the majority of the shell. The posterior is two smooth convex curves with a very distinct break of slope between them (2) where the skirt starts to grow outwards more than downwards. The anterior is convex on juvenile growth and straight on the adult skirt, with a break of slope where the two parts meet (3) . The aperture outline is usually a broad oval, approaching a circle on this specimen. The aperture rim is strongly curved up from the horizontal at the ends to fit the bowl shaped pit (4) .
Growth lines on the adult skirt are continuous around the whole shell (5). The thickness of this one, now opaque, has been increased by mantle secretions over the whole of the interior which is dark brown with some iridescence peripherally (6) plus a whitish layer (7) within the horseshoe-shaped scar of the pedal-retractor muscle. The exterior surface is smooth with no epizoic growth, but some have small amounts, including algae (see image 27 Patella pellucida. Growth Stage 4 stipe dweller (GS4s). July 2017. Tyne & Wear, England. © P.Lightfoot. ). Blue lines on the juvenile growth continue on the adult growth, alternating with red-brown rays (8) and turn red-brown on the latest growth near the rim. On this specimen there are a a distinct pedal-retractor-muscle scar (9), and a clearly marked, thin, white mantle-attachment scar (10).

Concise
Part 1, SHELL FORMS: 02 Patella pellucida. Growth Stage 2 (GS2). July 2012. Littoral. North Yorkshire, England. © P. Lightfoot.
Part 2, BODY & ANATOMY: 03 Patella pellucida. Growth Stage 3 (GS3). 2009. Sublittoral, Farne Islands, Northumberland, England. © P.Lightfoot.
Part, 3 HABITS & ECOLOGY: 04 Patella pellucida. Length 4.6mm. Growth Stage 3 (GS3). September 2016. Yorkshire, England. © P.Lightfoot.