Art. 11 NEW AMERICAN MARINE MOLLUSKS BARTSCH 33 



light ; inner lip heavy, thickened, curved ; parietal wall covered with 

 a rather thick callus that renders the peritreme complete. 



The type. Cat. No. 363784, U.S.N.M., was collected by Delos 

 Arnold at San Pedro, California. It has three and one-half whorls 

 and measures, length, 4 mm. ; height, 1.8 mm, ; greater diameter, 

 4.3 mm. 



VITRINELLA (DOCOMPHALA) COLUMBIANA, new species 



Plate 6, figs. 1, 2, 3 



Shell small, thin, depressed, helicoid, semitranslucent, bluish white. 

 As usual in this group, the outer surface is badly worn and shows 

 only rough eroded incremental lines which are best developed on the 

 last portion of the last whorls where they have a decidedly retractive 

 slant. The whorls are appressed except the last one which shows a 

 narrow channel at the summit near its termination; moderately well 

 rounded ; the early whorls are almost flattened on the upper surface, 

 the last one moderately well rounded. Periphery strongly rounded. 

 Base moderately rounded, moderately, broadly, openly umbilicated, 

 with the usual coarse notching on the columellar wall of the umbili- 

 cus. Aperture large, oblique, subcircular; peristome almost com- 

 plete except for a little notch on the parietal wall; outer lip thin; 

 the basal lip becoming thickened toward the columellar portion ; the 

 columella itself is very much thickened and slightly reflected. 



The type. Cat. No. 340848, U.S.N.M., was collected by Dr. I. S. 

 Oldroyd in Departure Bay, British Columbia. It has lost part of 

 the nuclear Avhorl but probably had 3.2 turns. It measures, length, 

 1.5 mm. ; greater diameter, S mm. ; lesser diameter, 2.2 mm. 



The present species is nearest related to Vit7'ineUa (DocofnphaJa) 

 steamsi Bartsch, from which it differs by its much narrower umbili- 

 cus and more subcircular aperture, also in having the excavation on 

 the umbilical wall much less pronounced. 



VFTRINELLA SMITHI. new species 



Plate 4, figs. 6, 8, 9 



Shell minute, pale brown. Nuclear whorls one and a half, smooth. 

 Postnuclear whorls two, well rounded, with well-impressed suture, 

 marked by strongly curved lines of growth only. Under surface 

 widely, openly umbilicated, marked by lines of growth only. The 

 last whorl strongly curved. Aperture slightly oblique, subcircular; 

 peristome thin, rendered complete by the thick callus on the parietal 

 wall. 



The type, Cat. No. 340813, U.S.N.M., was collected by A. G. Smith 

 at Whites Point, California. It measures, altitude, 0.6 mm, ; greater 

 diameter, 1.2 mm. 



The present species is nearest related to Vitrinella oldroydi, from 

 which it is at once distinguished by its much smaller size. 



