66 University of Michigan 
PAE Dial 
Elliptio. Hinge armature. 
Figure 22. KE. liebmanni cuatotolapamensis. Hinge armature of 
right valve of type (figure 22, plate IV). 
Figure 15. E. plexus distinctus. Hinge armature of right valve 
of figure 15, plate II. Young shell. 
Figure 11. &. plexus distinctus. Hinge armature of right valve 
of figure 11, plate II. Old shell. 
