. Bulletin - United States National Museum. Science. UNIVERSALITY DiST IB 7TED SPECIES. 77 Lingual membrane (Plate VII, Fig". U) long and narrow, arranged as in Patula. Morse gives 73 rows of 11-1-11 teetb, with 3 i^erfect lat- erals. I counted 10-1-10, with 3 perfect laterals. Centrals with the base of attachment long and narrow, expanded and notched at tehe outer lower angles, narrowed above and retlected; reflection very small, tricuspid, all the cusps bearing very short cutting points, the central one, as usual, longest. Laterals with the base of attachment twice as broad as in the ce
. Bulletin - United States National Museum. Science. UNIVERSALITY DiST IB 7TED SPECIES. 77 Lingual membrane (Plate VII, Fig". U) long and narrow, arranged as in Patula. Morse gives 73 rows of 11-1-11 teetb, with 3 i^erfect lat- erals. I counted 10-1-10, with 3 perfect laterals. Centrals with the base of attachment long and narrow, expanded and notched at tehe outer lower angles, narrowed above and retlected; reflection very small, tricuspid, all the cusps bearing very short cutting points, the central one, as usual, longest. Laterals with the base of attachment twice as broad as in the centrals, the inner lower angle suppressed, notched at the outer angle, broadly reflected above;'reflection larger than in the centrals, with one inner, long, slender cusp, reaching nearly the lower edge of the base of attachment, its cutting point quite reaching it, and one small outer side cusp, also bearing a distinct cutting point. Margi- nals low, wide, the reflection equaling the base of attachment and irreg- ularly denticulated along its edge, the inner cusp the longest and bifid. The dentition is quite that of Pupa, The above description is drawn from a specimen from Maine. The European form is figured by Moquin-Tandon with a median projection to the cutting edge of its jaw. Lehmann also figures a wide, slight projection to the cutting edge. A comparison of the desc!iption and figure of the dentition of the European specimens given by Thomson and Lehmann shows no specific difference. It will be noticed that Leh- mann's fljiure of the centrals shows a more developed reflection and cusp and no side cusps. I believe, however, that careful comparison will show no variation in this or other particulars. Vallonia piilchella, Muller. Shell widely umbilicated, depressed, slightly convex fig. 39. above, thin and transparent; epidermis colorless; whorls 4, very minutely striated, the last large and s^jreading at the aperture like a trumpet; aperture orbicular, a little dilated; per
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