Tuberculated, with six digitated, canaliculated rays, closed in the adult shell; outer lip internally striated.
P. scorpio. The Scorpion Pteroceras.
Species with digitations on the external edge, varying in number from six to ten.
3. Strombus. The Wing Shell. Thirty-two species.
As now defined and characterized by Lamarck, is easily distinguished by not having the winged aperture on the right side dentated or digitated, and the sinus therein always separated from the canal.
In some species the exterior is variously striated, smooth, wrinkled longitudinally, or tuberculated; the interior presents vivid and beautiful colours.
These shells frequently attain a large size and great solidity.
Shell thick, sub-involute, diconic, or ventricose, terminated like a cone before and behind; aperture very long, narrow, terminated anteriorly by a canal more or less elongated, recurved; the edges parallel; the external dilating with age, offering behind a gutter at its attachment to the spire, and before a sinus more posterior than the canal, through which passes the head of the animal; operculum horny, long, and narrow, with elements as if imbricated; the summit terminal.
Strombus gigas.
S. accipitrinus.