Art. 11 NEW AMERICAN MARINE MOLLUSKS BARTSCH 13 



The type, Cat. No. 363780, U.S.N.M., was collected by C. R. Or- 

 cutt in Todos Santos Bay. It has four and one-half whorls and 

 measures, length, 3 mm., diameter, 1.5 mm. 



ODOSTOMIA (CHRYSALLIDA) ERA, new species 



Plate 3, fig. 9 



Shell elongate- conic, semitransluscent, bluish white. Nuclear 

 whorls decollated. Postnuclear whorls narrowly shouldered at the 

 summit, slightly constricted at the suture, marked by strong slightly 

 protractively slanting axial ribs, of which 16 occur upon the second 

 and third, 18 upon the fourth to sixth, and 22 upon the last. These 

 ribs are a little narrower than the spaces that separate them. They 

 are crossed by six spiral cords, of which the first is at the summit. 

 This is rather weak, the one below the summit being the strongest, 

 and the next four are weaker and of about the same strength and 

 spacing. The spiral cords render the ribs slightly nodulose at their 

 junction, while the spaces inclosed between them are rather deep 

 pits of which those between the summit and the first spiral cord be- 

 low it have their long axis parallel with the axial ribs, while those 

 between the first and second are rounded. The rest are slightly 

 oblong, having their long axis parallel with the spiral cords. Su- 

 ture slightly constricted. Periphery of the last whorl well rounded. 

 Base moderately long, well rounded, marked by 11 strong broad 

 spiral cords which are separated by narrow channels. These cords 

 grow successively weaker from the periphery toward the tip of the 

 base. Aperture somewhat irregular effuse anteriorly ; posterior angle 

 acute ; outer lip thin, showing the external sculpture within by trans- 

 mitted light; inner lip twisted, reflected over and appressed to the 

 base for almost its entire length, provided with a moderately strong 

 fold at its insertion; parietal wall covered by a rather thick callus. 



The type, Cat. No. 217931, U.S.N.M., was collected by C. R. Or- 

 cutt in Magdalena Bay. It has seven and one half whorls having 

 lost the nucleus, and measures, length, 4.1 mm. ; diameter, 1.4 mm. 



ODOSTOMIA (CHRYSALLIDA) CUMSHEWAENSIS Bartsch 



Plate 3, fig. 10 



Odostomia (Ghrysallida) cumshetoaensis Bartsch, Proc. Biol. Soc. of 

 Wash., vol. 34, 1921, p. 34. 



Shell broadly elongate-conic, milk-white, nuclear whorls at least 

 two, obliquely immersed in the first of the postnuclear whorls, above 

 which about two-thirds of the nuclear spire projects. Postnuclear 

 whorls strongly rounded, constricted at the periphery, marked by 

 strong, retractively slanting axial ribs, of which 16 occur upon the 



