Occasional Papers of the Museum of Zoology 27 



by the so-called Rafinesque-Poulson "type." It has no bearmg 

 upon the nomenclature of this species, but is important for 

 the validity of the subgenus Scalenaria (Scalenilla) of the 

 genus Dysnomia (which see). 



Pleurobema lEwisi (Lea), 1861 



Type locality: Coosa River, Alabama. 



Unto lezvisi Lea, '61, p. 40. 



Pleuro'bema cor Simpson, '14, p. 765 (not L". cor Conrad, '34). 



Pleurobeniu leiuisi (Lea), Walker, '16*, p. 114. 



The synonymy of this species has been settled by Walker 

 and nothing remains to be added. 



Peeurobema simpsoni Vanatta, 19 15 



Type locality: Chattahoochee River, Columbus, Ga. 



Unio striatus Lea, '40, p. 287 (not U. striatus Goldfuss, '39). 

 Pleurobema striatum (Lea), Simpson, '14, p. 795. 

 Pleur. simpsoni Vanatta, '15, p. 539. 

 Unio striatus Lea, Walker, 'i6c, p. 47. 

 Pleurobema simpsoni Van., Walker, 'i8c, p. 173. 



The introduction of simpsoni Van. is justified (see Wal- 

 ker, 'iS-^). 



However, attention should be called to the probability that 

 U. modicus Lea ("57, p. 157), Pleurobema modicum Simpson 

 ('14, p. 794) and U. auiabalis Lea ('65, p. 89) and Pleuro- 

 bema amabile Simpson are synonyms of U . striatus. In this 

 case either would have priority, modicus being the earlier 

 name. 



Genus Elliptic Rafinesque, 1819 

 Type: Unio crassidens Lam. = U. nigra Raf. 



EUiptio Rafinesque, '19, p. 426; '20, p. 291 (no type named) ; Simp- 

 son, '00, 700, as section of Unio (type, U. crassidens Lam. = U. nigra 

 Raf.) ; Ortmann, '12, p. 65 (genus, type the same). 



Enrynia Rafinesque, '19, p. 426; '20, p. 297 (no type named) ; Herr- 



