74 BULLETIN 111, UNITED STATES NATIONAL MUSEUM. 



DENTALIUM (LAEVIDENTALIUM) CALLIPEPLUM Dall. 



Plate 12, fig. 5. 



1889. Dentalium callipeplum Dall, Bull. Miis. Comp. Zool., vol. 18, p. 419, pi. 



27, fig. 12 (b). 

 1889. Dentalium callipeplum Dall, Bull. 37, U. S. Nat. Mus., p. 76, pi. 27, 



fig. 12 (b). 

 1892. Dentalium callipeplum Dall, Trans. Wagner Free Inst. Phila., vol. 3, pt. 



2, p. 442. 

 1897. Dentalium {Laevidentalium) callipeplum, Pilsbry and Sharp, Tryon'sMan. 



Conch., vol. 17, p. 100, pi. 19, fig. 9. 

 1901. Dentalium callipeplum Dall and Simpson, Bull. U. S. Fish ('omm. for 



1900, vol. 1, p. 456. 

 1903. Dentalium callipeplum D xhL, Bull. 37, U. S. Nat. Mus., p. 76, pi. 27, fig. 



12 (b). 



The shell is strongly, evenly curved like a scimitar and rather rapidly 

 increasing in diameter, thin but strong; its section is round. In 

 color it is ivory or cream white, with some translucent patches, and 

 occasionally reflects a salmon tint on the tip and in the posterior 

 portion. The surface is very highly polished and shining. It is 

 entirely sculptureless; some growth lines appear as mere scratches, 

 but are difficult to distinguish on the glistening vitreous surface. A 

 shallow apical notch on the concave side is faintly indicated. It 

 measures — ^length, 62 mm.; diameter, 5 mm.; arc 7 (type). The 

 size is very uniform; the other museum specimens which measure 

 less are smaller only because younger. . 



The type, Cat. No. 94064, U.S.N.M., is from the U. S. B. F. Station 

 2400, between the Mississippi River delta and Cedar Keys, in 169 

 fathoms, gray mud, no temperature record given. 



This is a very striking shell, with a conspicuously high degree of 

 curvature, exceptionally brilliant glistening surface, and notable 

 for its ivory cream white color rather than the more usual bluish 

 white of most other species of Dentalium. These features, combined 

 with the total absence of any sculpture, make it easily recognized. 



The following are the museum records : 



Tvi^e. 



