"Cerion (Maynardia) yumaensis P. and V.

Shell cylindrical, the lower three whorls of equal diameter, those above tapering rapidly to form a short cone; white, mottled with fleshy-corneous above, or having this color appear in sparse streaks, or in most or all the intervals between the opaque white riblets throughout the shell. Surface evenly, regularly and closely ribbed, the ribs sep­arated by intervals slightly greater than their own width, about 29 on penult. whorl. Whorls 9½,  the earlier two corneons, first one smooth, next very minutely radially striate. Last whorl rounded below. Umbilical chink much compressed, the tract below it semi­lunar, defined by a groove. Aperture truncate-ovate, brown within; parietal lamina small, short. Columella truncated obliquely; lip expanded, not thickened; the parietal callus light. Alt. 24½; diam. 9½ mm. Yuma R., Hayti (Henry Prime); San Domingo (Gabb; Salle). While superficially like C. striatellum, the different arma­ture of the parietal wall at once distinguishes this species. The parietal lamina is much reduced, almost absent in some specimens."  (Pilsbry & Vanatta, 1895:209-210)