Occasional Papers of the Museum of Zoology 33 



Genus Lasmigona Rafinesque, 1831 

 Type: Alasmidonta costata Raf. 



Lasmigona Rafinesque, '31, p. 4 (no type named, two species including 

 costata). 



Symphynota Simpson, 'oqc, p. 662 (type, compressa Lea) (not Sym- 

 phynota Lea, '29; type, U. alata Say). 



Lasmigona Raf., Frierson, '14c, p. 40 (type, costata Raf.) ; Ort- 

 mann, '18, p. 557; Walker, '18", p. 2, and i8c, p. 177. 



Subgenus Pi^atynaias Walker, 1918 



Symphynota Simpson, 00c, p. 662 (type compressa (Lea), not Sym- 

 phynota Lea). 



Platynaias Walker, '18", p. 2 (type, compressa Lea). 



Subgenus Alasminota Ortmann, 1914 



Sulcularia Rafinesque, '31, p. 5 (type, Alasmodon badium Raf., not 

 identifiable) ; Ortmann, '18, p. 557. 



Alasminota Ortmann, '14, p. 43 (type, Margaritana holstonia Lea) ; 

 Walker, 'iS", p. 2. 



Subgenus Lasmigona s. s. Rafinesque, 183 1 



Lasmigona Rafinesque, 31, p. 4 (no type named) ; Simpson, '00'?, p. 

 564 (type, A. costata) ; Walker, '18", p. 2. 



Subgenus Pte;rosyna Rafinesque, 1831 



Pterosyna Rafinesque, "31, p. 5 (type, Alasmidonta complanata 

 Bar.) ; Walker, 'i8c, p. 61. 



Pterosygna Simpson, '00'', p. 665; Walker, '18", p. 2. 



"Frierson has shown that the original type of Lea's Sym- 

 phynota was Unio alatus Say, and it is therefore a synonym 

 of Proptcra Raf., and that consequently Lasmigona Raf. as 

 the earliest available name becomes the generic type" (Wal- 

 ker). Thus, also, the subgeneric name of Symphynota must 

 be changed, and Walker's name Platynaias has priority. The 

 name Sulcularia Raf., being founded upon an unidentifiable 

 species (see under L. holstonia), cannot be used, and Alasmi- 

 nota Ortm. stands. Pterosygna Simpson clearly is only a slip 

 of the pen for Pterosyna Raf. 



