148 
MARINE SHELLS OF WEST COAST OF NORTH AMERICA 
lated secondary sculpture. At regular intervals the whorls are marked by 
thick callous varices, which are usually of a lighter color than the re¬ 
mainder of the shell. Aperture large, subquadrate; posterior angle acute; 
outer lip thin, having three strong internal lirations, joining the whitish, 
short, straight, revolute columella at a little less than a right angle. By 
transmitted light two spiral light-color-bands become apparent on the 
inside of the lip, each of which is bordered by a zone of a darker color 
than the remaining shell. The general color effect of the exterior is that 
of a flesh-colored shell, covered by a dark epidermis, which is stretched 
tight over the ribs, permitting the lighter color beneath to shine through 
it at their summits. Length, 11.1; diameter, 3.2 mm. (Bartsch.) 
Type in United States National Museum, No. 15215b. Type locality, 
Monterey, California. 
Range. Monterey to San Diego, California. 
Turbonilla ambusta Dali and Bartsch, 1909 
Plate 56, fig. 13 
Bulletin 68, United States National Museum, 115; PI. 11, fig. 13. 
Shell medium-sized, slender, chestnut-brown. (Nuclear whorls decol¬ 
lated.) Post-nuclear whorls moderately rounded, appressed at the summit, 
slightly contracted at the periphery, marked by strong, rounded, slightly 
protractive axial ribs, of which sixteen occur upon the first and second, 
eighteen upon the third to seventh, the eighth has a strong varix, twenty 
upon the ninth, and twenty-two upon the tenth. On the penultimate whorl 
they are decidedly enfeebled. Intercostal spaces a little wider than the 
ribs, marked by ten, equal and equally incised, spiral lines, the space 
between which is crossed by numerous exceedingly fine spiral striations. 
Periphery and base of the last whorl well-rounded, marked by fine lines of 
growth and numerous very fine spiral striations. Aperture rhomboidal; 
posterior angle obtuse; outer lip thin, showing the external sculpture 
within; also color bands, of which a narrow white one occurs at the 
periphery, which is bounded on both sides by a brown band equaling it 
in width; another narrow brown band bordered on each side by a narrow 
white area occurs halfway between the periphery and the summit; colum¬ 
ella slender, slightly curved and somewhat revolute. Length, 10; diameter, 
2.3 mm. (Dali and Bartsch.) 
Type in United States National Museum, No. 152751. Type locality, 
off San Pedro in 10 fathoms. 
Range. San Pedro to San Diego, California. 
[4461 
