168 BULLETIN 91, UNITED STATES NATIONAL MUSEUM. 



nuclear whorls, and measures: Altitude, 1.2 mm.; greater diameter, 

 3 mm. 



VITRINELLA FACIRA, new species. 



Plate 34, figs. 5, 6, 7. 



Shell small, very depressed helicoid, thin, bluish white. The 

 nucleus consists of two stages: In the first, embracing one and one- 

 half turns, the surface is smooth; in the second stage, which em- 

 braces a little more than a turn, the surface is marked by numerous, 

 closely spaced, slender, spiral lirations. Postnuclear turns one and 

 one-fourth, appressed at the summit, well rounded, smooth, marked 

 by exceedingly fine lines of growth only. Periphery of the last whorl 

 well rounded. Base openly umbilicated, the umbilicus occupying a 

 little more than one-third of the diameter of the base, showing all 

 the whorls within, which are well rounded and marked by lines of 

 growth only. Aperture subcircular. 



The type, Cat. No. 249767a, U.S.N.M., comes from Port Alfred 

 (Coll. No. 1039). It measures: Altitude, 0.8 mm.; greater diameter, 

 2 mm. 



VITRINELLA (DOCOMPHALA) ARIFCA, new species. 

 Plate 36, figs. 7, 8, 9. 



Shell minute, rather thick, semitranslucent, bluish white. Nuclear 

 whorls one and one-half, well rounded, polished, smooth. Post- 

 nuclear turns one and one-fourth, strongly rounded, marked by two 

 slender spiral cords at the summit and microscopic spiral striations 

 on the rest of the surface. In addition to the spiral sculpture 

 the turns are marked by fine lines of growth. On the outer edge 

 of the aperture a number of strongly incised spiral scratches make 

 their appearance. Sutures well impressed. Periphery of the last 

 whorl well rounded. Base well rounded, strongly umbilicated. 

 The umbilicus is limited exteriorly by a strong, slightly tuberculated, 

 spiral cord. Three additional, strongly tuberculated, spiral cords, 

 which decrease in strength from the outer edge inward, mark the 

 inner wall of the umbilicus. The posterior portion of the base, 

 between the limiting spiral cord of the umbilicus and the periphery, 

 is smooth, while the other half adjoining the spiral cord is marked 

 by decidedly retractively slanting, oblique, slender, axial ribs which 

 anastomose with the spiral cord limiting the umbilicus. Aperture 

 circular; outer lip very thick; inner lip very strong and reflected, 

 strongly curved within, the outer edge oblique and straight. The 

 posterior angle of the aperture is filled by a strong callus. 



The type and another specimen of this species, Cat. No. 250554, 

 U.S.N.M., come from Port Alfred (Coll. No. 1427). The type meas- 

 ures: Altitude, 0.6 mm.; greater diameter, 1.1 mm. 



