Page:Natural History, Mollusca.djvu/206

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194
PECTINIBRANCHIATA.—SCALARIADÆ.

Genus Scalaria.

The shell is spiral, consisting of many whorls, assuming a turreted form, ornamented with many elevated ribs, which cross the whorls in the same direction as the length of the shell; the aperture is rounded, with the lip thickened and entire. There is a horny operculum.

The animal has an angularly lunate head, with two long pointed tentacles, and eyes immersed at their bases; the mouth, which opens below, has a retractile proboscis; the mantle is rudimentary; the foot is triangular, grooved beneath, and furnished in front with a fold.

Natural History - Mollusca - Precious Wentletrap.png

In the principal section of the genus, confined to the warmer parts of the globe, the whorls or turns of the spire do not touch each other in any direction: these are designated true Wentletraps. In this division is placed the shell above alluded to,