34 University of Michigan 



Lasmigona (Platynaias) compressa (Lea), 1829 

 Type locality: Ohio and Norman's Kill, Albany, N. Y. 



Unio viridis Rafinesque, '20, p. 293. 



Symphynota compressa Lea, '29, p. 450, pi. 12, f. 22; Simpson, '14, 

 p. 481. 



Lasmigona viridis (Rai.) ^^ Symphynota compressa Lea, Friersoti', 

 '15, P- 59- 



Unio viridis Raf. Not =1 Symphynota compressa Lea, Walker, '15, 

 p. 74. 



Unio viridis Ra.{. =:^ Symphynota viridis Con., '36, Vanatta, '15, p. 

 554 ("type" examined). 



Lasmigona {Platynaias) compressa (Lea), Walker, '18", p. 2; 18^, 

 p. 177. 



Lasmigona {Platynaias) viridis (Raf.), Ortmann, '19, p. 116. 



Opinion of Ortmann: 



The description of Rafinesque's U. viridis may be referred 

 to two species, Symph. compressa Lea, a western form, and 

 U. subviridis Con. {=tappaniana Lea), an eastern form. It 

 is impossible to make out which was intended. Identifying it 

 with the western form, the size (only 1^2 inches) does not 

 agree; identifying it with the eastern form, the locality (Ken- 

 tucky drainage) does not fit. Moreover, the two forms are 

 so very similar that it is hard to distinguish young compressa 

 from subviridis of the same size. This uncertainty of the 

 determination is also expressed by the rather lively dispute 

 over U. viridis, and thus we are to regard this species as not 

 identifiable. The determination of the "type" by Vanatta is 

 irrelevant, and thus compressa Lea is valid. 



Opinion of Walker: 



Rafinesque's U. znridis is not this species, but the subviridis 

 Con. or tappaniama Lea (see under subviridis). Thus, Lea's 

 name compressa stands. 



Both vieivs lead to the same, conclusion. However, the 

 identity of U. viridis is important for the nomenclature of 

 the next species {subviridis), which see. 



