UNIO.— Plate XVII. 



Species Hi). (Mus. Cuming.) 



Unio tuugidulus. Un. lestf'l sitlicordato-ovatd, gibbosd, 

 antice rotundald, posiice Jlexuoso-triangulald, obscure 

 lineari-sulcald ; pallide virescenie-olivaeed. 



Till-: SLIGHTLY-SWOLLEN Unio. Shell somewhat cor- 

 dately ovate, gibljous, anteriorly rounded, posteriorly 



ilexiionsly two-augletl, obsfiirely linearly grooved ; 



pale greenish-olive. 

 Lea, Pro. Acad. Nat. Sci. Phil. 18.58, p. 40 ; Obs. vol. 



viii. p. 6(5. pi. 5. f. 211. 

 Ilab. Cumberland lliver, North America. 



The posterior side of this sijecies is lightly <loubl 

 angled. 



species 



