A static red jaw with strong ribs (1:) is set into the top of the mouth (2:); it retains food (3:) loosened by the radula(4:).
All images photographed in water; colours fade when dried.
Left: ventral view of odontophore dissected from head of C. hortensis.
Centre: ventral view of head feeding on thin, hard, dried film of flour on glass.
Right: three views of extracted jaw.
1: chitinous jaw with two corrugations (number varies 2-4) forming ribs on outer face.
2: chitinous jaw with four corrugations forming ribs; set into the top of the mouth; held at an angle down to substrate; retaining flour rasped towards it by radula. No cutting or scraping by the jaw observed; lack of erosion signs on edge make these actions improbable. Jaw observed to be static during each feeding-stroke of radula.
3: flour retained by jaw
4: broad, tongue-shaped radula covered with thousands of teeth extended from mouth to rasp up flour. (See image 24Ch 24 Cepaea hortensis. Radula and radula sac. Pennine foothills, V.C. Derbyshire, England. August 2018. )
5: sole of foot.
6: film of dried flour paste on glass.
7: outer face of jaw with three corrugations forming ribs.
8: inner face of jaw; photographed while stood on edge to show horseshoe shape.
9: angled view of jaw.
10: edge which touches substrate when in use.
11: thin, translucent, chitinous fringe which is embedded in the buccal mass in life (shrunken and barely perceptible on dried specimens).
12: horseshoe shaped flange protruding from inner face into buccal mass in life.

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