66 BULLETIN 111, UNITED STATES NATIONAL MUSEUM. 



DENTALIUM (GRAPTACME) EBOREUM Conrad. 



Plate 10, figs. 3, 4, 5, 8, 9; plate 11, fig. 6. 



1846. Dentalium eboreum CoT<!KKT>, Proc. Acad. Nat. S(i. Phila., vol. 3, p. 27. 

 1885. Dentalium leptum Bush, Trans. Conn. Acad. Arts and Si., vol. 6, p. 470, 



pi. 45, fig. 18, 18a. 

 1885. Dentalium leptum Bush, Report of Com. of Fish and Fisheries for 1883, p. 



586 [84]. 

 1889. Dentalium leptum, Dall, Bull. Mus. Comp. Zool., vol. 17, p. 421. 

 1889. Dentalium leptum, Dall, Bull. 37, U. S. Nat. Mus., p. 76. 

 1889. Dentalium matara Dall, Bull. Mus. Comp. Zool., vol. 18, p. 420. 

 1889. Dentalium matara Dall, Bull. 37, U. S. Nat. Mus., p. 76. 

 1892. Dentalium leptum., Dall, Trans. Wagner Free Inst., Phila., vol. 3, pt. 2. 



. p. 440. 

 1897. Dentalium eboreum, Pilsbry and Sharp, Tryon's Man. Conch., vol. 17, p. 



89, pi. 16, figs. 47-49, 55, 56. 

 1897. Dentalium leptum, Pilsbry and Sharp, Tryon's Man. Conch., vol. 17, p. 



89, pi. 16, fig. 50. 

 1897. Dentalium matara, Pilsbry and Sharp, Tryon's Man. Conch., vol. 17, p. 



105, pi. 18, figs. 14-18. 

 1901. Dentalium matara Dall and Simpson, Bull. U. S. Fish Com. for 1900, vol. 



1, p. 456. 

 1903. Dentalium leptum, Dall, Bull. 37, U. S. Nat. Mus., p. 76. 

 1903. Dentalium matara Dall, Bull. 37, U. S. Nat. Mus., p. 76. 



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

 with a long slightly arched tip. The color is a salmon pink, some- 

 times yellowish, generally fading to white, first on the anterior 

 portion, then finally over the entire shell in all but fresh specimens. 

 The surface is highly polished, shining and vitreous, though often 

 variegated with milky, less translucent patches. The sculpture is con- 

 fined to the tip only and consists of about 20 very fine raised longi- 

 tudinal lines, visible only under a lens; all the balance of the shell is 

 perfectly smooth save for slight growth irregularities. There is a 

 rather deep, narrow apical notch on the convex side. In old speci- 

 mens where the tip has been lost a projecting thin sheath of the 

 inner shell layer from the posterior aperture is frequently de- 

 veloped, and in this case the apical slit is preserved and reproduced 

 in the protruding sheath, and it is sometimes even repeated, though 

 in lesser degree, on the concave side as well. Average specimens 

 measure — length, from 25 to 35mm.; diameter, 2.5 mm.; with an 

 arc of 2. An adult specimen of large size with tip intact would 

 measure about — ^length, 62-65 mm.; diameter, 3 mm.; with an arc 

 of 3.5 to 4. 



The type of Dentalium eboreum is in the collection of the Phila- 

 delphia Academy of Sciences; topo types in museum collection. Cat. 

 No. 152957, U.S.N.M., are from Sarasota Pass, Florida. 



The type of Dentalium leptum, Cat. No. 41562, U.S.N.M., are from 

 off Hatteras, in 16 fathoms, from the U. S. B. F. Station 2276; bot- 

 tom of gray sand and broken shells. 



