123, SEDENTARIA. DENTALIUM. 
TRIBE II.—MALDANIA. 
Branchie of the animal intermediate, tube open at both 
ends. 
Genus III. — DEN TALIUM. — Zinneus. 
Generic Character. — Shell tubular, open at both ends, 
arcuated, increasing in the diameter towards the wider ex- 
tremity, where the aperture is large and round; opening of 
the pointed end very small, and with a lateral fissure in 
some species ; external surface ribbed, striated, or smooth. 
Dentalium nitens. Plate X. fig. 24, 
The shells of this genus have the miniature form of an elephant’s tusk. 
They inhabit all seas, and are pretty numerous in species. They occur in a 
fossil state in the Blue Marls of France, the London Clay at Highgate Hill, 
and Avignon, France; Folkstone, and Barton Cliffs, and a few are met with 
in the Limestones of Bagnor and Exmouth. 
