UXIO.— Plate XXXII. 



oblique angulalo, ad li'rmhinin prodiictn, (icuminaio, 

 margine veutrali ad Medium cu)ivexo, ninryinc dorsali 

 paulo declivi. 

 Burrough's Unio. Shell oval-obloug, oblique, solid, con- 

 centrically irregularly sulcated, white within, black- 

 ish green epidermis without, obliquely angularly and 

 divergently ridged at the umboes and towards the 

 middle, anterior side short, rather round, posterior 



side elongated, obliquely angulated, produced and 

 acnmiuated at the extremity, ventral margin convex 

 in the middle, dorsal margin a little sloping. 



Lea, Trans. Amer. Thil. vol. v. t. 10. f. 27. 



Hab. River Panama, South America. 



The strong coarse A and V shaped wrinkles covering 



the umboTial region, and reaching to near the middle of 



the shell, are strongly characteristic of this species. 



