Drums are either cylindrical or conical.
The southern end rises in the conical Mount Oros, and the Panhellenian ridge stretches northward with narrow fertile valleys on either side.
The mouth, with its jaws, forms a conical outgrowth which projects backwards, so that its apex lies beneath the prothorax.
Summits of the lower incisors, before they are worn, with a deep transverse groove, dividing it into an anterior and a posterior cusp. Canines long, strong and conical.
In some forms the coiling disappears in the adult, leaving the shell simply conical as in Patellidae, Fissurellidae, &c., and in some cases the shell is coiled in one plane, e.g.
