Pictured above is an adult snail collected from a residential garden in Eugene, Lane County, Oregon in May, 2014.

Born, I. A., 1780.  Testacea Museiu Caesarei Vindobonensis, quae jussu Mariae Theresiae Augustae. J. P. Kraus, Vienna. ii + 1-442 + xvii [unpaginated indices].

Favanne, J. de and J. G de Favanne, 1780.  La conchyliologie, histoire naturelle des coquillages de mer, d'eau douce, terrestres et fossiles .... par M. Desallier d'Argenville .... troisième édition 3 vols., De Bure, Paris.

Müller, O. F., 1774. Vermium Terrestrium et Fluviatilium seu animalium infusorium, helminthicorum, et testaceorum non marinorum succincta historia. Heinick and Faber, Havnia and Lipsia. xxxvi + 1-214 + x [unpaginated indices].