Original Combination:

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Original Description:

Cave Town, Md., 64,720; very numerous in stony places. This is a limestone region, and the red soil is largely the result of limestone decomposition. The same form of Triodopsis was found at Gettysburg, Pa., 64,710, and in Allegheny Co., Md., between Green and Polish Mountains, 64,716, Chewsville, Md., 64,717, at Fairview, summit of North Mountain, Md., and in Morgan Co., W. Va., opposite Hancock, 64,718. It is common around Philadelphia, where typical tridentata also occurs.
This form is distinguished from typical tridentata by the lower position of the upper lip-tooth, the latter part of the parietal lamella being directed toward this tooth or to a point above it, whilst in the type the lip-teeth are more separated and the latter portion of the parietal lamella is directed toward a point on the peristome between them. The variety is more coarsely striated also. The number of whorls (5) is the same in variety and type. The measurements of three individuals are as follows:
Alt. 7 diam. 14 mm. (Philadelphia).
Alt. 6 ¾ diam. 13 ½ “ (Cave Town, Md., largest).
Alt. 6 diam. 11 " ( Cave Town, Md., smallest).
The upper lip- tooth is sometimes broader than the lower, and occasionally a trifle "inflected." The parietal blade is slightly arcuate.