T. undosus.
T. variegatus. The trumpet Triton. Pl. [26], fig. 5.
The smoothest species, oblong, ventricose, tubiform; aperture dilated; suture of the spire crenulated; pillar lip grooved obliquely; colour pale purple, clouded and spotted with brown.
T. cutaceus. The rough-skin Triton.
Species with spire rather short, always very tuberculated, often umbilicated; a sinus at the posterior junction of the two edges.
T. anus. The grinning Triton.
Species similar to the T. cutaceus, but having the aperture surrounded by a thin dilated membrane and irregular teeth.
FAMILY XVII.
Alata. Three genera.
1. Rostellaria. Three species.
Lamarck formed this genus from the Strombus of Linnæus on account of having a sinus in the lower part of the right margin contiguous to the canal. The beak is generally curved, and short in comparison to the length of the spire, but sometimes it is straight, and equal in length to the other part of the shell.