Tentaculita
Tentaculita
a class of extinct marine mollusks that existed from the Silurian to the Devonian. The shell was conical, 3–7 cm in length, and closed at the narrow end; in cross section it was rounded, with a smooth or sculptured surface. The shell cavity was usually divided into chambers by transverse septa. The body of the mollusk was in the largest, anterior chamber. Tentaculita are important in the stratigraphy of Devonian deposits.