S. communis.
S. Australis.
S. raricosta.
S. pretiosa. The precious Scalaria, more commonly called the Wentle Trap, or Winding Staircase. Pl. [23], fig. 1.
This shell has its spiral whorls separate, and appears like an attenuated tube evolved round a cone; spire detached, with a deep umbilicus; volutions connected by longitudinal ribs; body extremely ventricose; colour cream yellow.
S. communis. The common Scalaria, or false Wentle Trap.
More taper and elongated than the S. pretiosa. It has no umbilicus, and the whorls are closely united.
3. Delphinula. Three species.
A marine shell, which, like the Scalaria, has a round aperture, but its solidity and pearly substance distinguishes it from the Cyclostoma, which is terrestrial.
Shell thick, pearly in the interior, sub-discoid or conical; the spiral whorls sometimes detached, rounded, spiny, with a large umbilicus; aperture round or multrigonal, not modified; edges perfectly united with a small spire, tuberculated exteriorly.