84 
MARINE SHELLS OF WEST COAST OF NORTH AMERICA 
of oblique, incremental lines, which are quite deeply angulated convexly, 
posteriorly just a little above the middle of the whorl; aperture narrow, 
oblique; outer lip thin, arcuate anteriorly; inner lip smooth and incrusted; 
posterior sinus deep and remote from suture; canal narrow, slightly re¬ 
curved, over one-third of the aperture. Long., 35; lat., 11; body whorl, 
8.5; diameter, 13 mm. (Arnold.) 
Type in United States National Museum. Type locality, Pleistocene, 
San Pedro, California. 
Range. Forrester Island, Alaska, to San Diego, California. Fossil 
at San Pedro, California. 
This was described as Pleurotonm smithi by Arnold. 
Antiplanes santarosana Dali, 1919 
Plate 6, fig. 1 
Proceedings of the United States National Museum, 24:515; 56: PI. 11, fig. 3. 
Shell elongated, slender, acute, with twelve whorls, of an olivaceous 
or pinkish brown; the interior of the aperture of a pale rufescent hue; 
whorls rounded, suture very distinct, sculpture chiefly of incremental lines 
and a faint spiral striation mostly below the periphery; anal fasciole limited 
by slightly raised lines; nucleus small, inflated, smooth; aperture narrow, 
with a short, wide canal; pillar solid, short, obliquely truncate; outer lip 
thin, produced, with a deep anal sulcus a little in advance of the sutural 
margin of the whorl. Operculum normal. Long, of shell, 36; of aperture 
and canal, 11.5; max. diam., 9 mm. (Dali.) 
Type in United States National Museum, No. 109198. Type locality, 
off Santa Rosa Island, California, in 53 fathoms. 
Range. Off Santa Rosa Island to San Diego, California. 
This was described as Pleurotoma santarosana by Dali. 
Antiplanes diaulax Dali, 1908 
Proceedings of the United States National Museum, 34:247. 
Shell small, acute, conic, brownish, with about nine whorls; suture 
distinct, not appressed; surface smooth, except for incremental lines and 
two impressed shallow spiral channels near the periphery of the whorls; 
the surface just behind each channel is slightly raised, forming a flattish 
band about as wide and high as the channel is wide and deep; on the base 
and canal there are also some faint spiral threads; the sides of the spire 
are flattish, the periphery nearest the succeeding suture which is laid on 
the anterior edge of the anterior channel, thus giving the whorls a sort 
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