Strophiops (Umbonis) mutatoria Maynard and Clapp in Maynard, 1920
5. S. mutatoria.
Smaller and more slender than 3, 1.00 by .26; lines of growth and sometimes low costae on ultimate whorl; margin and lower tooth as in last, but there is a small upper tooth: color, similar. In area south of last. Map 1, 6. Common, 500, all dead. Plate 1. figs. 3 4.