Page:Journal of the Academy of Natural Sciences of Philadelphia (IA journalofacademy01acaduoft).pdf/25

Rh formed. For several specimens of this shell I am indebted to Mr. Titian Peale.

Shell oval or oblong; aperture large, oblique; columella narrowed.

S. ovalis. Shell suboval, pale yellowish, diaphanous, very thin and fragile, with nearly three oblique volutions. Body very large. Spire small, but little prominent, somewhat obtuse. Aperture longitudinally subovate, large. Collumella much narrowed so as almost to permit the view of the interior apex, from the base of the shell. Scarcely any calcareous deposit on the pillar lip. Length nine-twentieths of an inch, aperture seven-twentieths.

Inhabits marshy grounds in shaded situations. Common.

Collection of the Academy.

Animal longer than its shell, furnished with four tentacula, the two superior ones longer, cylindrical, supporting the eyes; inferior ones, short, conic. Colour page with minute black points, which are assembled into fascia on the sides and fillets on the neck above; neck granulate above, a black line passes each side of the neck, from the tip of the oculiferous tentacula, gradually disappearing under the shell. Front truncate, quadrate.

When the animal is living, so vitreous is the shell, that all the markings of its body are plainly discernable. So that although the shell is of a straw-colour, immaculate, it appears of a dusky hue, with a remarkable white, flexuous, longitudical vitta on the back, arising from the su-