\ 



(3RT.MANN : UnIONID/E OF WESTERN PENNSYLVANIA. 183 



4. Unio ellipsis Lea = Obova7-ia ellipsis (Lea). 



5. " cariosus Say = Lampsilis vcntricosa (Barnes). 



Lavipsilis cariosa (Say) is an eastern form, and absent from the 

 Ohio drainage, yet it has often been confounded with its western rep- 

 resentative L. vcntricosa, so that it is beyond doubt that Z. vcntricosa 

 is intended. 



6. Unio pyramidatus Lea = Quadrula obliq^ia (Lamarck) form : 



pyramidata ( Lea ) . 

 Unio trigonus Lea. 

 This species remains doubtful. The true typical Quadrula trigona 

 has never been found in the Ohio drainage in Pennsylvania, although 

 certain individuals of Q. ruhiginosa (Lea) incline toward it. Such 

 specimens have recently been collected in Allegheny County. 



7. Unio alatus Lea= Propter a a lata (Say). 



All of the foregoing seven species have been subsequently found in 

 Allegheny County, except Obovaria ellipsis, which, however, exists in 

 the Ohio in Beaver County. At the present time, only four of these forms 

 live in Allegheny County : Lampsilis vcntricosa, 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 

 Unionidce 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 vcntricosa oval a (Say). 



2. Unio rectus Lamarck = Lampsilis recta (Lamarck). 



3. Unio pilaris Lea = Quadrula subrotunda (Lea) juv. 



This probably is a misidentification, young specimens of Quad?'ula 

 subrotunda being intended. Quadrula 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 luteola (Lamarck). 



6. ** gracilis Lea = /'rtf/z'^ra^rdf^/Z/.y (Lea). 



7. '* rubiginosus Lea = Quadrula rubigi?wsa {l.tz) . 



8. '* orbiculatus Hildreth = Lampsilis orbiculata (Hildreth). 



9. '* securis Lea = Plagiola securis (Lea). 



