Sandbowl snail  (Catinella arenaria)

Information supplied by English Nature:

http://www.englishnature.org.uk/

Calcareous: containing free calcium carbonate, chalky.
Carrion: dead flesh.
Hermaphrodite: possessing both male and female sex organs.
Whorls: in animals, the spiral or convolutions in the shell of a snail. In plants, a set of leaves, flowers, or branches that spring from a stem at the same point and encircle it.