13. S. constrictus - var tenuistrictus - GSC 5342 S. Sask. Riv. opp. mouth Swift-Current Riv. Sask. - Pierre-Fox Hills Coll. T.C.Weston 1889. Originally labeled D. nicolleti, these are smaller forms with not as high a body chamber, some differences in ribbing, which is generally fine, becoming finer on outer end body chamber. Has coarse or bundled ribbing on straight umbilical shoulder which may form bulge, 5-7 pairs strong ventro-lateral nodes on body chamber. This is undoubtedly like nicolleti but markedly different in detail. As JAS points out it resembles Nowaks illustrations of tenuistrictus, but the max. height of whorl on B.C. is not as great as in Nowaks spec. Ribs cross venter without forward bend. Apt. Izct "beak?" Normal pst ribbing to here fine ribs nodes chiefly confined to umbilical bundling area. umbilical bundling 8.