No. 33. DENTALIUM. 

 Tooth Shell. Inhabitant a Terebella. 



Shell univalve, tubular, straight, or slightly curved, with the cavity open at 

 both ends, and undivided. — Linnmus. There are three families. Greuelin 

 enumerates, all together, twenty-one species of this genus, some of which are 

 found only in a fossil state. 



The shells of this s;enus are singular; resembling, in miniature, an elephant's 

 tusk. The principal distinctions are in magnitude, curvature, and the num- 

 ber of ribs and grooves with which some of the species are marked. 



These shells are all marine; they may be found on sandy banks of beaches 

 at low water, generally in a perpendicular or oblique direction, beneath the 

 sand or mud, and are discoverable by a slight depression of the surface. 



Family 1st. With longitudinal ribs. 



Scientific name. 



Rectum, 



Elephantinum, 



Aprinum, 



Locality. 

 Indian Seas. 

 Indian and Europ. Seas, 



Mauritius. 

 Indian Seas. 



Scientific name. 

 Striatum, 

 Dental is, 

 Fasciatum, 

 Imperforatum, 



Locality. 

 Sicily, Cornwall. 

 Med., Amb., W. ofEng. 

 Sicily. 

 Sandwich, Falmouth. 



Family 2d. With annidar strife. 



Politum, 

 Eburneum, 



India, Sicily. 

 do. 



Trachea, 



Milton in Devonshire. 



Family 3d. Smooth. 



Entalis, Britain, India, Norway. Minutum, Med., Devonshire. 



Corneum, African Ocean. Pellucidum, North Sea. 



Gadus, British Channel. 



