183 ANNALS OF THE CARNEGIE MUSEUM. 
4. Unio ellipsis Lea = Odovaria ellipsis (Lea). 
5. §* cariosus Say = Lampsilis ventricosa (Barnes). 
Lampsilis cariosa (Say) is an eastern form, and absent from the 
Ohio drainage, yet it has often been confounded with its western rep- 
resentative Z. ventricosa, so that it is beyond doubt that Z. ventricosa 
is intended. 
6. Unio pyramidatus Lea = Quadrula obliqua (Lamarck) form: 
pyramidata (Lea). 
Unio trigonus Lea. 
This species remains doubtful. The true typical Quadruda trigona 
has never been found in the Ohio drainage in Pennsylvania, although 
certain individuals of Q. vuhiginosa (Lea) incline toward it. Such 
specimens have recently been collected in Allegheny County. 
7. Unio alatus Lea = Proftera alata (Say). 
All of the foregoing seven species have been subsequently found in 
Allegheny County, except Odovaria ellipsis, which, however, exists in 
the Ohio in Beaver County. At the present time, only four of these forms 
live in Allegheny County: Lampsilis ventricosa, Lampsilis ligamentina, 
Proptera alata, Unio gibbosus, and only at one place ; viz.: in the north- 
eastern corner of the county in the Allegheny River. As to the rest, 
all the rivers in Allegheny County are so hopelessly polluted that no 
Unionide are any longer found. 
To this list, G. H. Clapp (Nautilus, 8, 1895, p. 116) has added 
a supplement, namely : 
1. Unio ovatus Say = Lampsilis ventricosa ovata (Say). 
2. Unio rectus Lamarck = Lampsvlis recta (Lamarck). 
3. Unio pilaris Lea = Quadrula subrotunda (Lea) juv. 
This probably is a misidentification, young specimens of Quadru/a 
subrotunda being intended. Qwuadrula pilaris stands very close to 
subrotunda, and since subrotunda was, and is, rather abundant in our 
rivers, and is missing in both Stupakoff’s and Clapp’s list, it is more 
than probable that the latter species should be recorded for Allegheny 
County. 
4. Unio crassidens Lamarck. 
5. Unio luteolus Lamarck = Lampsilis /uteola (Lamarck). 
6. ‘ gracilis Lea = Proptera gracilis (Lea). 
7. ‘* rubiginosus Lea = Quadrula rubiginosa (Lea). 
8. ‘ orbiculatus Hildreth = Lampsilis orbiculata (Hildreth). 
g. ‘* securis Lea = Plagiola securis (Lea). 
