CataIwOgui; Recently Described Moeeusca 171 



Genus AMBLEMA Rafinesque, 1820. 



Amblema Rafinesque, Monographie, 1820, p. 314. 



Creitodcnta Schluter, Verz. meiner Conch., 1836, p. 33 ; Simpson, Syn., 



1900, p. 766; Desc. Cat., 1914, p. 813. 

 Type: Amblema costata H^i. 



Genus MEGALONAIAS Utterback, 191 5 



Mcgnlonaias Utterback, Amer. Mid. Nat., IV, 191 5, p. 123. 

 Type : Unio heros Say. 



Genus ROTUNDARIA Rafinesque, 1820. 



Rotimdaria Rafinesque, Monographic, 1820, p. 308; Simpson, Syn., 1900, p. 



794; Desc. Cat., 1914, p. 903. 

 Type: Obliquaria tuber cidata Hai. 



Genus FUSCONAIA Simpson, 1900. 



Fusconaia Simpson, Syn., 1900, p. 784; Desc. Cat., 1914, p. 865. 

 Type : Unio trigonus Lea. 



Genus PTETHOBASUS Simpson, 1900. 



Plethobasiis Simpson, Syn., 1900, p. 764; Desc. Cat., 1914, p. 805. 

 Type: Unio crsopiis Green. 



Genus PLEUROBEMA Rafinesque. 

 PlEurobEma .^sopus (Green). 



This species has been referred to Obliquaria cyphya Raf. by Conrad, 

 Call, Ortmann and others. Vanatta (140, p. 556) states that the shell in 

 the Poulson collection so labelled is this species. If identifiable from the 

 original description, cyphya would have priority. 



This species is the type of Simpson's section Plctliobasus, which Ort- 

 mann (79, p. 259) has raised to generic rank. 



PlEurobema argenteum pannosum Simpson. 



This is a Fusconaia and a synonym of F. oaarkeiisis (Call) according to 

 Ortmann (84, p. 63). 



Pleurobema barnesianum (Lea). 



Is a Fusconaia and includes meredithii Lea, piidicum Lea, lyonii Lea, 

 tellicoensis Lea and lenticulare Lea according to Ortmann (84, p. 59). 



