128 
MARINE SHELLS OF WEST COAST OF NORTH AMERICA 
more or less regular, spiral grooves of somewhat varying width, which 
inclose spaces between them of a width about equal to the grooves, the 
space between the first of these and the last on the spire is a rather wide 
band, devoid of sculpture, excepting the fine spiral striations, which cover 
the entire surface of the shell, in addition to the coarser sculpture already 
described. Aperture small, subquadrate, posterior angle obtuse; outer lip 
moderately strong; inner lip oblique, straight and slightly reflected; 
parietal wall covered by a thick callus. Length, 13.8; diameter, 3.2 mm. 
(Bartsch.) 
Type in United States National Museum, No. 250626. Type locality, 
off San Diego Bay, California. 
Range. Known only from type locality. 
Turbonilla ina Bartsch, 1917 
Plate 51, fig. 10 
Proceedings of the United States National Museum , 52:649; PI. 44, fig. 10. 
Shell broadly, elongate-conic, bright brown, excepting the nucleus, 
which is white. Nuclear whorls, two and one-half, planorboid, having 
their axis almost at right angles to that of the succeeding turns, in the 
first of which they are about one-third immersed. Post-nuclear whorls 
feebly rounded, appressed at the summit, marked by rather feeble, almost 
vertical, axial ribs, of which eighteen occur upon the second and third, 
twenty upon the fourth and fifth, and twenty-two upon the remaining 
whorls. Intercostal spaces feebly impressed, about as wide as the ribs, 
crossed by eleven incised spiral lines between the sutures, of these the 
fifth is the widest, being fully twice as wide as the third and sixth, which 
are of equal strength, the remaining are much more slender and also 
of equal strength. In spacing the first is about as far anterior to the 
summit as the second is distant from the third, or the fourth from the 
fifth, or the fifth from the sixth, while the space between the first and 
second, and those between the sixth and the seventh, are about equal, the 
spiral markings pass up on the sides of the ribs and the stronger ones tend 
to cross their summit. Suture moderately constricted. Periphery of the 
last whorl decidedly angulated. Base short, slightly rounded, marked by 
the very feeble continuations of the axial ribs, which become evanescent 
before reaching the middle of the whorls, and thirteen incised spiral lines, 
which are about equally spaced, the first one below the periphery being a 
little nearer to its neighbor than the spacing between the rest, the space be¬ 
tween the seventh line of the spire and the first incised spiral basal line 
is a broad, smooth band. Aperture subquadrate, posterior angle obtuse; 
[426 ] 
