CLASS GASTROPODA 
103 
Alvania sanjuanensis Bartsch, 1921 
Proceedings of the Biological Society of Washington, 34: 37. 
Shell moderately large, chestnut brown excepting the tip, which is a 
little paler, and the extreme base, which is also lighter. Nuclear whorls 
one and a half, well rounded. (The sculpture of the nuclear whorls eroded 
in all the shells seen except in a very small fraction of the last turn in the 
type, which presents a finely, somewhat wavy, spirally lirate surface. I am 
not quite certain whether axial threads are present or not.) Nuclear whorls 
strongly shouldered at the summit, strongly rounded, marked on the first 
turn by three strong spiral cords, which occupy the anterior half of the 
turn; on the second turn a fourth cord occurs a little anterior to the 
median line between the summit and the first strong cord, while on the 
next turn a fifth slender thread makes its appearance between the summit 
and this cord. This last cord at the summit never attains a strength as 
great as the third anterior to it, while the second one is fully as strong on 
the penultimate turn. In addition to these spiral cords, the shell is marked 
by rather weak axial ribs, of which twenty-four occur upon the second, 
twenty-six upon the third, and about thirty-two upon the last turn; on this 
they are decidedly enfeebled. The junction of the axial ribs and spiral 
cords forms feeble nodules. The entire surface of the spire between ribs 
and interspaces is crossed by fine spiral and axial threads which lend it a 
fine clothlike texture. Suture strongly constricted. Periphery of the last 
whorl well rounded. Base moderately long, well rounded, marked by seven 
equally spaced spiral threads, of which the seventh immediately behind the 
inner lip is feeble. The rest are almost as wide as the spaces that separate 
them. The axial ribs do not extend over the base, but the fine sculpture 
described for the spire is also present here. Aperture ovate; posterior 
angle obtuse; outer lip thin at the edge, strongly curved; inner lip strongly 
curved, reflected and appressed to the base except at the extreme tip; 
parietal wall covered by a thick callus, which renders the peritreme com¬ 
plete. Altitude, 3; diameter, 1.5 mm. (Bartsch.) 
Type in United States National Museum, No. 334487. TyP e locality, 
San Juan Islands, Puget Sound, Washington. 
Range. Puget Sound, Washington. 
Alvania dalli Bartsch, 1927 
Proceedings of the United States National Museum , 70:30; PI. 3, fig. 6. 
Shell small, thin, semitranslucent, bluish white. Nuclear whorls one 
and one-half, strongly rounded, finely granular. Postnuclear whorls rather 
inflated, strongly rounded, appressed at the summit, marked by five low, 
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