186 SYSTEMATIC PALEONTOLOGY 



Superfamily GYMNOGLOSSA. 



Family PYRAMIDELLIDAE. 



Genus ODOSTOMIA Fleming. 

 Subgenus CHRYSALLIDA Carpenter. 



Odostomia (Chrysallida) seminuda (Adams) 

 Plate L, Figs. 3, 4. 



Jaminia seminuda Adams, 1839, Jour. Bost. Soc. Nat. Hist., vol. ii, p. 280, 



pi. iv, fig. 13. 

 Odostomia granulatus Holmes, 1859. Post-Pi. Fos. S. C, pp. 86, 87, pi. xiii, 



figs. 11, 11a, lib. 

 Not Acteon granulatus H. C. Lea. 

 Odostomia seminuda Dall, 1889. Bull. U. S. Nat. Mus., No. 37, p. 130, pi. lii, 



fig. 10. 

 Odontostomia seminuda Dall, 1892, Trans. Wagner Free Inst. Sci., vol. iii, 



pt. 2, p. 251. 



Description. — " Shell , acute-conic, glossy white, diaphanous; whorls, 

 about seven, convex; upper whorls and upper half of the body whorl, 

 rugose longitudinally, with three impressed revolving lines, presenting a 

 decussate oi granulous appearance ; upon the lower half of the body whorl 

 are four additional impressed revolving lines, one of which runs around 

 at the inferior abrupt termination of the rugae, which are eighteen to 

 twenty; suture broad, divided by an indistinct spiral ridge; apex acute; 

 aperture elliptical, one-third the length of the shell; labrum not thick- 

 ened, pectinated by the revolving lines, which are distinctly seen upon 

 the inner side ; inferior margin effuse ; columella with a single sub-oblique 

 fold, arcuate, reflexed; operculum?" Adams, 1839. 



This species is very closely related to, if not identical with 0. mela- 

 noides (Conrad) described in 1830 from the Miocene. It is possible that 

 Adams' name of seminuda should be regarded as a synonym of melanoides. 

 There are no sharply distinguishing characteristics, although the Mio- 

 cene form is slightly stouter than the Eecent. 0. seminuda is found in 

 the Pleistocene of Maryland and South Carolina and in the Eecent ranges 

 from Massachusetts Bay to the Gulf of Mexico. 



Length, 45 mm.; width, 2 mm. 



