Occasional Papers of the Museum of Zoology 33 
Genus LAsMIcoNA Rafinesque, 1831 
Type: Alasmidonta costata Raf. 
Lasmigona Rafinesque, ’31, p. 4 (no type named, two species including 
costata). 
Symphynota Simpson, ’00°, p. 662 (type, compressa Lea) (not Sym- 
phynota Lea, ’29; type, U. alata Say). 
Lasmigona Raf., Frierson, ’14°, p. 40 (type, costata Ratpis Ort= 
mann, “18, p. 557; Walker, ’18*, p. 2, and 18¢, p. 177. 
Subgenus PLatyNnatAs Walker, 1918 
Symphynota Simpson, o0¢, 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, 718, p. 557. 
Alasminota Ortmann, 14, p. 43 (type, Margaritana holstonia Wears 
Walker, ’18*, p. 2. 
Subgenus LASMIGONA s. s. Rafinesque, 1831 
Lasmigona Rafinesque, 31, p. 4 (no type named) ; Simpson, ’00°, p. 
564 (type, A. costata) ; Walker, ’18*, p. 2. 
Subgenus PrerosyNA Rafinesque, 1831 
Pterosyna Rafinesque, °31, p. 5 (type, Alasmidonta complanata 
Bar.) ; Walker, ’18c, p. 61. 
Pterosygna Simpson, ’oo”, 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. 
