26 Patella pellucida. Length 11mm. Growth Stage 5 stipe dweller (GS5s). March 2011. Menai Strait, Wales.
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 27Pp flic.kr/p/YRpsdK ). 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 Key id. features: 1Pp flic.kr/p/Z4FxDe
Part 1, SHELL FORMS: 2Pp flic.kr/p/Z4FxAi
Part 2, BODY & ANATOMY: 3Pp flic.kr/p/Z4FxtK
Part, 3 HABITS & ECOLOGY: 4Pp flic.kr/p/Z4Fx9M
Sets of OTHER SPECIES: www.flickr.com/photos/56388191@N08/collections/
26 Patella pellucida. Length 11mm. Growth Stage 5 stipe dweller (GS5s). March 2011. Menai Strait, Wales.
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 27Pp flic.kr/p/YRpsdK ). 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 Key id. features: 1Pp flic.kr/p/Z4FxDe
Part 1, SHELL FORMS: 2Pp flic.kr/p/Z4FxAi
Part 2, BODY & ANATOMY: 3Pp flic.kr/p/Z4FxtK
Part, 3 HABITS & ECOLOGY: 4Pp flic.kr/p/Z4Fx9M
Sets of OTHER SPECIES: www.flickr.com/photos/56388191@N08/collections/