CLASS GASTROPODA 
217 
incremental lines. The upper sides of the whorls are moderately and 
evenly rounded. Sutures well-marked. Periphery of the last whorl well- 
rounded. Base moderately well-rounded, openly umbilicated to the very 
apex. Columellar wall of the base well-rounded (not concaved). Aperture 
decidedly oblique, broadly oval; outer lip thin; parietal wall covered by a 
rather strong callus, which partly fills the posterior angle. Greater diam¬ 
eter, 2.1; lesser diameter, 1.6; altitude, 0.8 mm. (Bartsch.) 
Type in United States National Museum, No. 158777. Type locality, 
Point Loma, California. 
Range. San Pedro, California, to Point Abreojos, Lower California. 
Vitrinella eshnauri Bartsch, 1907 
Plate 106, figs. 5, 7, 9 
Proceedings of the United States National Museum, 32:168; fig. 2. 
Shell moderately elevated, subglobose, thin, almost transparent, glassy. 
Nepionic whorls 1J4, scarcely differentiated from those which follow, well- 
rounded, smooth. Succeeding whorls well-rounded, somewhat inflated, 
marked only by exceedingly fine lines of growth. Sutures well-impressed. 
Periphery of the last whorl well-rounded. Base moderately rounded, 
marked only by incremental lines, with narrow but open umbilicus, which 
is obsoletely angled at the outer edge. Columellar wall of umbilicus ver¬ 
tical from the outer edge to within a short distance of the parietal wall, 
where it bends outward to join the preceding turn. Aperture decidedly 
oblique, almost circular; outer lip thin and translucent; columella quite 
strong and decidedly curved; parietal wall covered by a moderate callus, 
which forms an acute angle with the posterior margin of the lip. Greater 
diameter, 2.3; lesser diameter, 1.9; altitude, 1.3 mm. (Bartsch.) 
Type in United States National Museum, No. 127557. Type locality, 
San Pedro, California. 
Range. Known only from type locality. 
Vitrinella alaskensis Bartsch, 1907 
Plate 106, figs. 8, 10, 12 
Proceedings of the United States National Museum, 32:168; fig. 3. 
Shell small, subglobose, semitransparent. Nepionic whorls 1%, well- 
rounded, smooth. Succeeding turns somewhat inflated, well-rounded, sepa¬ 
rated by strongly impressed sutures, marked only by incremental lines. 
Periphery and base of the last whorl well-rounded. The latter narrowly 
and openly umbilicated to the very apex. Columellar wall of the umbilicus 
not flattened nor angulated at the outer edge, but evenly rounded with the 
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