76 
University of Michigan 
PAE Vile 
Lampsilis and Actinonaias. 
Figures 39-42. L. rovirosai sanjuanensis. (Figure 40 is type). 
Figures 43-45. Arroyo Hueyapam shells, like A. umbrosa. 
Bigures 46, 47. San Juan River shells, like A. explicata. 
