178 
MARINE SHELLS OF WEST COAST OF NORTH AMERICA 
Odostomia excisa Bartsch, 1912 
Proceedings of the United States National Museum, 42:276; PI. 36, fig. 8. 
Shell moderately large, elongate-ovate, yellowish-white. Nuclear whorls 
decollated. Post-nuclear whorls well-rounded, appressed at the summit, 
marked by four, equally strong but not equally spaced, incised, spiral lines 
between the sutures. The fourth of these is immediately above the 
periphery, while the first is as far below the summit as the third is posterior 
to the fourth. The second line divides the space between the first and 
third into equal halves, which are about one and a half times as wide as 
the spaces included between the third and fourth incised spirals. In 
addition to the spiral sculpture the whorls are crossed by numerous, fine, 
decidedly retractive, incremental lines. Periphery of the last whorl some¬ 
what inflated, well-rounded. Base moderately long and moderately rounded, 
crossed by 8 strongly incised, equal, spiral lines, which are a little 
stronger than those occurring on the spire. These lines become exceedingly 
closely spaced between the periphery and the umbilical area. The axial 
sculpture on the base is of the same character and strength as that 
appearing on the spire. All of the incised, spiral lines on the base and spire 
are crossed by very slender, axial threads, which lend these channels a 
somewhat pitted appearance. Sutures well-impressed. Aperture moder¬ 
ately large, oval, effuse anteriorly; posterior angle acute; outer lip thin, 
showing the external sculpture within; inner lip oblique, moderately long, 
somewhat reflected, and re-enforced for the greater part of its length by 
the attenuated base, provided with an oblique fold at its insertion; parietal 
wall glazed with a thin callus. Length, 3.9; diameter, 1.9 mm. (Bartsch.) 
Type in United States National Museum, No. 194518. Type locality, 
Catalina Island, California. 
Range. Known only from type locality. 
Odostomia farma Dali and Bartsch, 1909 
Bulletin 68, United States National Museum, 188; PI. 20, figs. 1, la. 
Shell elongate, ovate, cream-colored. Nuclear whorls at least two, 
marked with three slender, spiral lirations, the apex being deeply obliquely 
immersed in the first of the succeeding turns. The junction of the nucleus 
and the post-nuclear whorls is marked by a varix. Post-nuclear whorls 
well-rounded, marked by three, equal and subequally spaced, spiral grooves 
which are crossed by slender axial riblets, the combination of grooves and 
ribs giving the whorls a pitted appearance. The four raised spaces bounded 
by the spiral grooves are finely spirally striated. Suture deeply channeled. 
Periphery of the last whorl marked by a spiral groove. Base of the last 
1476 ] 
