196 
MARINE SHELLS OF WEST COAST OF NORTH AMERICA 
the base. Aperture iridescent inside, nacreous; operculum very thin, multi¬ 
spiral, with about 10 elegantly radiately rugulose whorls. (Carpenter.) 
Alt., 8; diam., 8 mm. (Tryon and Pilsbry, Manual of Conchology.) 
Type in ? Type locality, California. 
Range. Forrester Island, Alaska, to San Diego and the Coronado 
Islands. Also Japan. Fossil: Pliocene, San Pedro. 
Solariella triplostephanus Dali, 1910 
Nautilus, 24:34. Dali, Bulletin 112, United States National Museum; PI. 18, figs. 1, 2. 
Shell trochiform, with six tabulate whorls; nucleus very minute, glassy, 
slightly tilted; subsequent whorls flat above, with closely appressed suture ; 
three strong spirals girdle the whorls; one at the shoulder strongly beaded; 
one at the middle of the whorl minutely undulate, and the third at the 
suture, simple, and obscured on all the whorls but the last by the suture 
being laid against it; on the last whorl there may be a few micro¬ 
scopic spiral threadlets between the shoulder and the median spiral; be¬ 
tween the anterior spiral and the edge of the umbilicus on the base are 
six or eight fine-channeled spiral grooves; the chord bordering the funicular 
umbilicus is coarsely beaded; within the umbilicus are three or more similar 
but smaller beaded threads; axial sculpture consisting of fine, sharp, uni¬ 
form, and closely set elevated lines corresponding with the lines of growth, 
but frequently more or less obsolete; aperture nearly circular, oblique, 
with simple edges, hardly interrupted on the body; throat pearly. Height 
of shell, 5.25; of aperture, 2.5; maximum diameter of shell, 7.0 mm. 
(Dali.) 
Type in United States National Museum, No. 97001. Type locality, 
near La Paz, Lower California, in 12 fathoms, sand. 
Range. Ofif San Diego, California, and south to Panama, in deep 
water. 
Solariella rhyssa Dali, 1919 
Proceedings of the United States National Museum , 56:360. 
Shell small, trochiform, translucent, with four whorls, including a 
smooth nucleus of a whorl and a half; suture distinct; whorl-section 
circular; axial sculpture of (on the last whorl 35) narrow threadlike ribs, 
regularly spaced, uniform, the interspaces wider; extending from the 
suture to the verge of the umbilicus; spiral sculpture of minute spiral 
threads showing in the interspaces under a lens, but not modifying the 
axial ribs; umbilicus wide, funicular; aperture circular, simple, sharp- 
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