88 
MARINE SHELLS OF WEST COAST OF NORTH AMERICA 
deeply channeled suture decidedly coronated. Intercostal spaces deep, 
of about double the width of the ribs, interrupted suddenly at the de¬ 
cidedly angulated (almost keeled) periphery of the last whorl, beyond 
which they reappear. Base strongly contracted, quite short, marked 
by the faint continuations of the axial ribs, which extend to the umbilical 
region. Outer lip fractured; aperture of columella very strong, some¬ 
what curved and revolute, provided with a subobsolete oblique fold. 
Length, 3.3; diameter, 1.1 mm. (Dali and Bartsch.) 
Type in United States National Museum, No. 163009. Type locality, 
San Diego, California. 
Range. Catalina Island to San Diego, California. 
Turbonilla gilli delmontensis Dali and Bartsch, 1907 
Plate 49, fig. 12 
Proceedings of the United States National Museum, 33: 494; PI. 44, fig. 7. 
Shell similar to T. gilli, but much more stout and less turreted, with 
the ribs less strongly developed and the peripheral thickening only weakly 
represented. Length, 3.4; diameter, 1.2 mm. (Dali and Bartsch.) 
Type in United States National Museum, No. 195921. Type locality, 
off Del Monte, Monterey, California, in 12 fathoms. 
Range. Known only from type locality. 
Turbonilla acra Dali and Bartsch, 1909 
Plate 49, fig. 14 
Bulletin 68, United States National Museum, 32; PL 2, fig. 14. 
Shell very long and slender, milk-white. (Nuclear whorls decollated.) 
Post-nuclear whorls high between the sutures, varying in outline, the 
first to eleventh being flattened, almost cylindric, with very strongly 
shouldered summits, the rest moderately well-rounded, with less strongly 
shouldered summits. Axial ribs very strong on the first eleven whorls, 
less so and more rounded on the remaining. There are about fourteen 
upon each of the first eleven turns, twenty-two upon the twelfth, twenty 
upon the thirteenth, fourteenth, and fifteenth, and about thirty much en¬ 
feebled and irregular ones upon the last turn, where they pass over the 
well-rounded periphery and base to the umbilical region. On the early 
turns the axial ribs terminate as strong, exserted cusps at the summit; 
on the last turn they are merely rounded. Early sutures strongly marked, 
later ones well-impressed. Aperture ovate, posterior angle acute; outer 
lip thin; columella slender, almost straight, obliquely inserted. Length, 
10; diameter, 1.8 mm. (Dali and Bartsch.) 
