The shell is narrowly umbilicate, conic, a little obtuse at the apex, corneous, nearly smooth. The whorls are very convex, separated by a deep suture, the last whorl tubular. The aperture is distinctly oblique, almost circular, the upper end rounded, but a trifle more narrowly so than the base. It projects but little beyond the preceding whorl laterally. The peristome is thin, continuous, scarcely or barely in contact with the preceding whorl above.
Length 3.1, diam. 1.9, length aperture 1.1 mm.; 5 whorls (type).
Length 2.8, diam. 1.6, length aperture 0.85 mm.
Operculum having the spiral rather large, the nucleus being above the lower third.
This little species resembles Lyogyrus by its tubular whorls of small calibre. The whorls are more convex and increase less rapidly than in Amnicola walkeriana, which is also less slender. A. schrockingeri Ffld. has less deeply convex whorls, and the apex is more acute. A. bakeriana is much larger, with a more obtuse apex.
Found in Short Point Bay, Oneida Lake, near shore, in 3 feet of water, bottom of sand with algae; also in Lower South Bay, etc. Collected by Mr. F. C. Baker.
It is named for Dr. John M. Clarke, the distinguished Director of the Museum of the State of New York.
Amnicola oneida, n. sp.
The shell is typically more slender than A. lustrica, turrited-conic, narrowly umbilicate, corneous, minutely striate. The apex is slightly obtuse, but the first whorl projects visibly, as in lustrica, whorls very convex, parted by a deep suture. The aperture is ovate, small, its length contained more than 3 times in that of the shell; upper extremity narrowly rounded. The peristome is continuous, thin, very briefly in contact with the preceding whorl above.
Length 4, diam. 2, length of aperture 1.25 mm.; 6 whorls.