76 



BULLETIN 111, UNITED STATES NATIONAL MUSEUM. 



DENTALIUM (LAEVIDENTALIUM) LIODON Pilsbry and Sharp. 



1897. Dentalium (LaeridentaJium) liodon Pilsbry and Sharp, Tryon's Man. 

 Conch., vol. 17, p. 107, pi. 21, figs. 37-39. 



The shell is moderately curved, rather slender, thin but strong, 

 with a subcircular aperture, a little dorso-ventrally compressed. 

 Color bluish white, subtranslucent, but more opaque in the middle 

 portion; the surface is brilliantly polished. It is sculptureless, save 

 for occasional circular grooves indicating growth lines. A narrow 

 V-shaped apical notch on the convex or the concave side, or even 

 more or less laterally placed, is a peculiarly variable feature. 



The type, in the Philadelphia Academy of Sciences, is from St. 

 Martin (E. Marie) and measures — length, 25.3 mm.; diameter, 2 mm. 



This species may be at once distinguished from Dentalium calle- 

 'pe'plum by its smaller size and lesser degree of curvature, from D. per- 

 longum by its shorter shell. D. liodon is a shallow to moderately deep 

 water mollusk. 



DENTALIUM (LAEVIDENTALIUM) LIODON LIODON Pilsbry and Sharp. 



Plate 12, figs. 2, 3, 4. 



The description of this, the typical subspecies of Dentalium liodon^ 

 coincides with that of the species itself, with the restriction, however, 

 to those forms only that have the apical notch on the convex side. 



The type, which is in the Philadelphia Academy of Sciences, is the 

 same as oiD. liodon and measures — length, 25.3 mm. ; diameter, 2 mm. 



The museum lots are: One specimen, Cat. No. 61188, U.S.N.M., 

 was collected by C. T. Simpson in Honduras, and is a beach shell; 

 one specimen, Cat. No. 19729, U.S.N.M., from Barbados; one speci- 

 men. Cat. No. 341902, U.S.N.M., was taken by the State University of 

 Iowa Expedition of 1918 at their station 49, off Bridgetown, Bar- 

 bados, in 80 fathoms; one specimen, Cat. No. 314903, U.S.N.M., 



