DENTALIIDAE 331 



Subgenus Graptacme Pilsbry and Sharp 1897 

 Dentalimn eboreum Conrad Ivory Tusk 



Figure 696 



North CaroHna to both sides of Florida and the West Indies. 



I to 2^ inches in length, glossy, ivory-white to pinkish. Apical slit 

 deep, narrow and on the convex side. Apical end with about 20 very fine 

 longitudinal scratches. Common in sandy, shallow areas. 



Dentalium semistriolatum Guilding Half-scratched Tusk 



South Florida and the West Indies. 



About I inch in length. Similar to eboreum, but curved more, with 

 apical slits on the side, and its color translucent-white with milky patches. 

 Some specimens may be reddish near the apical end. Common from i to 90 

 fathoms. 



Dentalium calamus Dall Reed Tusk 



North Carolina to east Florida and the Greater Antilles. 



% to I inch in length, almost straight and glassy-white. Most of the 

 shell has minute, longitudinal scratches (about 16 per mm.). The apical end 

 is sealed over by a bulbous cap which bears a small slit. Uncommon. 



Subgenus Episiphon Pilsbry and Sharp 1897 



Shells very small, needle-like, wholly lacking longitudinal sculpture and, 

 as in some other •subgenera, having a projecting, thin tube at the posterior 

 end after the tip is broken or lost. Only one species in the Western Atlantic. 



Dentalium sowerbyi Guilding Sowerby's Tusk 



North Carolina and Texas to Florida and the Lesser Antilles. 



10 to 15 mm. in length. Needle-like, not fragile, curved, glossy-white. 

 Crowded rings of growth microscopic on tip. Apex without slit and from it 

 projects a very thin inner tube. Erroneously known previously as D. filum 

 Sowerby. Commonly dredged from 17 to 180 fathoms. 



