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, pl. 12, f. 22; Simpson, ’14, 
p. 481. : 
Lasmigona viridis (Raf.) = Symphynota compressa lea, Frierson, 
"15, DP. 59. 
Unio viridis Raf. Not =Symphynota compressa lea, Walker, ’15, 
Dp. 74. . 
Unio viridis Raf. = Symphynota viridis Con., ’36, Vanatta, ’15, p. 
554 (‘“‘type” examined). 
Lasmigona (Platynaias) compressa (Lea), Walker, ’18*, p. 2; 18¢, 
DLA. 
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% 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. viridis is not this species, but the subviridis 
Con. or tappaniana Lea (see under subviridis). ‘Thus, Lea’s 
name compressa stands. 
Both views lead to the same conclusion. However, the 
identity of U. viridis is important for the nomenclature of 
the next species (subviridis), which see. 
