AND DESCRIPTIONS OF NEW SPECIES. 91 



Unio Castaneus. Plate XL fig. 21. 



Testa subellipticd, ineequilaterali, obliqud, inflatn; valvulis'crassis; dentibus car- 

 dinalibus magnis; lateralibus subrectis brevibusque; margaritd maximefulgente et 

 iridescente. 



Shell subelliptical, inequilateral, oblique, inflated; valves thick; cardinal teeth 

 large; lateral teeth nearly straight and short; nacre very pearly and iridescent. 



Hab. Alabama river, Judge Tait. 



My Cabinet. 

 Cabinet of Professor Vanuxem. 

 Cabinet of P. H. Nickliu. 

 Diam. '6, Length -8, Breadth 1 inch. 



Shell subelliptical, oblique ; substance of the shell thick ; beaks pro- 

 minent and situated towards the anterior margin ; ligament short ; epi- 

 dermis slightly wrinkled, dark brown anterior to the umbonial slope, 

 and yellowish posterior, where there are a few obsolete rays ; cardinal 

 tooth large, slightly elevated, deeply cleft in the left valve and emerg- 

 ing from a pit in the right valve; lateral teeth short and nearly 

 straight ; posterior and anterior cicatrices both distinct ; dorsal cicatrices 

 situated on the under part of the cardinal tooth within the cavity ; cavity 

 of the beaks wide and shallow ; nacre very pearly and iridescent. 



Hemarlis. — This small species is allied to the U. circulus (Nob.) 

 in colour and to U. ellipsis (Nob.) in form. It has the posterior slope 

 yellow, which is so in the circulus. The specimen described and 

 figured here is not more than one fourth of the size of an imperfect 

 specimen which accompanied it. 



Unio Multistriatus. Plate XIL fig. 22. 



Testa striata, transversa, inaquilaterali; natibus prominulis; umbonibus rugo- 

 sis; dente cardinali obliquo, laminato, in valvuld sinistra unico, in dextrd duplici; 

 dente laterali longo et subrccto; margaritd caruleo-albd. 



