PLATE IL 

 Strophomexa blainvillei (page 28). 



Figure 1. A cast of the inner surface of the ventral valve. 

 " \a. Longitudinal section, through the beak. 

 "16. A cast of the interior of part of a dorsal valve. 

 " Ic. \ih Muscular impressions of 3. perplana from the Pal. N. Y., Vol. 4. 



SXROPIIOMi^XA MAGNIVENTKA (page 22) 



Figure 2. Inner snrface of ventral valve. 

 " 2a. Longitudinal section. 



Strophomexa varistriata (page 26). 



F ig Ventral valve. 



Strophomexa ixequiradiata (page 24). 



Figure 4. Ventral valve. 



" Aa. Area of ventral valve. 



Strophomexa Irexe (page 27). 



Figure 5. Ventral valve. 



" ba. Longitudinal section. 



Strophomexa tullia (fage 29). 



Figure 6. Cast of inner surface of ventral valve. 



" Q>a. Cast of inner surface of part of a large ventra! valve. 



