82 University of Michigan 
PILATES, 2K IL 
Lampsilis and Actinonaias. Hinge armature. 
Figure 53. Lampsilis ruthvenit. Left valve of figure 53, plate XIII. 
‘Figure 48. Actinonaias walkeri. Right valve of figure 48, plate X. 
Figure 49. Actinonaias walkeri. Weft valve of figure 49, plates IX 
and X. 
