Occasional Papers of the Museum of Zoology 71 
Dysnomia flexuosa (Raf.) =U. foliatus Hild., Agassiz, ’52, p. 43. 
Truncilla (Dysnomia) foliata (Hild.), Simpson, ’14, p. 18. 
Epioblasma biloba Raf.=U. foliatus Hild., Frierson, ’14*, p. 7. 
Trun, flexuosa (Raf.) =Tr. foliata (Hild.), Vanatta, ’15, p. 557 
(“type” examined). 
Tr. foliata (Hild.) = Obl. flexuosa Raf.= Ep. biloba Raf., Walker, 
"18¢, p. 186 (“if identifiable”). 
Conrad and Vanatta have found that the so-called Rafin- 
esque-Poulson “type” of fexuosa is the same as foliatus Hild. 
The original description of feruosa mentions two gentle ele- 
vations of the shell, and between them a wide and flat depres- 
sion. This is a very prominent character of the species and 
cannot be applied to any other shell. Also the description of 
the margins of the shell as “‘flexuous” is significant. Thus the 
specific name f#exuosa stands. 
As to biloba, its recognition is important with regard to the 
validity of the subgenus Epioblasma (as against Dysnomia). 
Férussac is not sure about the identity of his authentic speci- 
men of biloba. The phrase “‘belly bilobed” has suggested the 
idea that it is the female of f#eruosa, but this is not bilobed 
below, but bisinuata, with only one large lobe. Also the 
description of the shell as elliptical does not fit, for it is tri- 
angular. Further, the beaks are not prominent, as described, 
and nothing is said about the very striking feature, the two 
ridges of the shell, and the deep and wide radial furrow. 
Thus the description of biloba is not recognizable, and with 
this name also that of the subgenus, Epioblasma, goes into the 
discard. 
