106 
MARINE SHELLS OF WEST COAST OF NORTH AMERICA 
which they are slightly immersed. Post-nuclear whorls well-rounded, 
appressed at the summit, marked by slender, curved, moderately regular, 
slightly protractive, axial ribs, of which sixteen occur upon the first to 
fifth, eighteen upon the sixth, twenty-two upon the seventh and eighth, 
twenty-four upon the ninth and tenth, and twenty-six upon the penulti¬ 
mate turn. Intercostal spaces moderately impressed, terminating a little 
posterior to the periphery of the whorls. The summit of the succeeding 
turns falls a little anterior to the termination of the intercostal pits and 
leaves a smooth band in the suture. Suture moderately constricted. 
Periphery of the last whorl obtusely angulated. Base moderately long, 
weakly rounded. The entire surface of the shell is marked by micro¬ 
scopic striations. Aperture large, broad, subquadrate, somewhat effuse 
at the junction of the basal and the outer lip, posterior angle obtuse; 
outer lip very thin showing the external sculpture within; inner lip 
decidedly oblique, slightly curved and somewhat revolute; parietal wall 
covered by a thin callus. Length, 9.2; diameter, 2 mm. (Bartsch.) 
Type in Geological Survey of Canada Collection. Type locality, 
Barkley Sound, Vancouver Island, British Columbia. 
Range. Known only from type locality. 
Turbonilla doredona Bartsch, 1917 
Plate 51, fig. 3 
Proceedings of the United States National Museum, 52:642; PI. 44, fig. 3. 
Shell very regularly, broadly elongate, conic, yellowish white. Nuclear 
whorls, two and three-fourths, strongly rounded, smooth, forming a 
strongly elevated spire having its axis at right angles to that of the suc¬ 
ceeding turns, in the first of which the side of the last volution is about 
one-fifth immersed. Postnuclear whorl well rounded, slightly curved at 
the appressed summit, marked by rather distantly spaced, slender, narrow, 
well-rounded axial ribs which become somewhat flattened and enfeebled 
toward the summit. Of these ribs, 18 occur upon the first, 16 upon the 
second to fourth, and 18 upon the remaining turns. Intercostal spaces 
about two and one-half times as wide as the ribs, terminating at little 
posterior to the suture, thus leaving a very narrow plain band between 
their termination and the summit of the succeeding turn. Suture moder¬ 
ately constricted. Periphery of the last whorl well rounded. Base short, 
strongly rounded, marked by the feeble continuations of the axial ribs 
which become evanescent before reaching the middle of the base. Entire 
surface of the shell crossed by rather marked, subequally strong and sub- 
equally spaced, deeply incised spiral striations. Aperture subquadrate; 
posterior angle obtuse (outer lip partly fractured); inner lip thick, almost 
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