76 University of Michigan 



PLATE VIII 



Lampsilis and Actinonaias. 



Figures 39-42. L. rovirosai saujiiamnsis. (Figure 40 is type). 

 Figures 43-45. Arroyo Hueyapam shells, like A. umbrosa. 

 Figures 46, 47. San Juan River shells, like A. explicata. 



