Page:Natural History, Mollusca.djvu/203

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191
STYLIFER.

Family Pyramidelladæ.

This is an extensive group of small, and for the most part, minute shells, which often display much beauty to the close observer; their forms being in general elegantly turreted, their surfaces smooth, often polished, or ornamented with the most beautiful and elaborate sculpture. The aperture is entire, and not lengthened into a canal; the pillar or inner lip is often plaited.

The animals are furnished with a retractile proboscis, and with tentacles of varying form, with the eyes not set on footstalks, but immersed in the bases. The tongue is remarkable for being unarmed with teeth.

As the fossil remains of a former world present the extinct forms of this family in great numbers and variety, the group is one of much interest to the geologist.


Genus Stylifer.

I select the genus Stylifer to illustrate the family, because of its singular form and still more curious economy, rather than for its abundance in these latitudes, for it is represented on the British coast by a single species, and that of very rare occurrence.

The shell is somewhat globose, with the tip slender, and projecting in the form of a little point or style; its surface is smooth and polished; its whorls are numerous. There is no operculum.

The animal has slender tentacles, and eyes immersed at their bases; the mantle has been described as thick, fleshy, cup-shaped, enveloping