40 BULLETIN 111, UNITED STATES NATIONAL MUSEUM. 



DENTALIUM (ANTALIS) OCCIDENTALE Stimpson. 



1841. Dentalium dentale, Gould, Invert. Mass., p. 155, pi. 1, fig. 5 (not D. dentalis 



Linnaeus). 

 1851. Dentalium occidentale Stimpson, Shells of New England, p. 28 (based upon 



Gould, no description). 

 1870. Dentalium dentale, Gould (Binney Ed.), Invert. Mass., p. 266. 

 1874. Dentalium occidentale, Smith and Hargar, Trans. Conn. Acad, of Arts and 



Sci., vol. 3, pt. 1, p. 23. 

 1880. Dentalium occidentale, Verrill, Proc. U. S. Nat. Mus., vol. 3, p. 394. 

 1880. Dentalium occidentale, Verrill, Amer. Journ. Sci., ser. 3, vol. 20, No. 119, 



p. 392. 

 1882. Dentalium occidentale, Verrill, Trans. Conn. Acad, of Arts and Sci., vol. 5, 



pi. 42, figs. 16-18. 

 1884. Dentalium occidentale, Verrill, Trans. Conn. Acad, of Arts and Sci., vol. 6, 



pt. 1, p. 216. 

 1884. Dentalium occidentale, Verrill, Rept. Comm. Fish and Fisheries for 1883, 



p. 573, pi. 28, figs. 123-125. 

 1884. Dentalium occidentale. Bush, Rept. Comm. Fish and Fisheries for 1883, p. 



717. 

 1893. Dentalium occidentale. Bush, Bull. Museum of Comp. Zool., vol. 23, No. 6, 



p. 224. 

 1897. Dentalium (Antalis) occidentale, Pilsbry and Sharp, Tryon'sMan. Conch., 



vol. 17, p. 47, pi. 9, figs. 41-43; pi. 13, figs. 9-11. 

 1901. Dentalium occidentale, Whiteaves, Cat. Marine Invert, of E. Canada, p. 152. 

 1904. Dentalium occidentale, Blaney, Proc. Boston Soc. Nat. Hist., vol. 32, No. 2, 



p. 30. 

 1908. Dentalium occidentale, Lermond, Shells of Maine, p. 15. 

 1915. Dentalium occidentale, Johnson, Occ. Papers Boston Soc. Nat. Hist., vol. 7, 



p. 83. 



The shell is moderately curved, chiefly in its posterior fourth, and 

 increases regularly in diameter; the section is round. Some speci- 

 mens show a slight dorsoventral compression in the middle posterior 

 portion. Its color is of a dirty white, showing occasionally an ivory 

 tinge; the surface is dull and lusterless. A thin outer layer, a central 

 softer chalky layer, and an inner hard and compact hluish white 

 layer, form the substance of the shell. The two outer layers are 

 subject to erosion, in consequence of which the majority of living 

 specimens present a patchy, worn appearance. The scidpture con- 

 sists of 16 primary longitudinal, quite sharply defined, narrow rounded 

 riblets, inclosing coarsely surfaced spaces between, of al)out equal or 

 somewhat greater width than that of the riblets. These riblets are 

 better developed upon the posterior portion, but in some well-pre- 

 served adult specimens they persist, though with decreasing definite- 

 ness, to the end. Some intercalation may be present. As these 

 sculptural features are mostly confined to the outer shell layer, 

 erosion often obliterates all but mere traces of them. There is an 

 apical notch on the convex side, but this character is often obscure. 



