Occasional Papers of the Museum of Zoology 25 



Quadrula pyramidata (Lea), Simpson, '14, p. 888. 



Quad, ritbra (Raf.)=Q. pyramidata (Lea), Vanatta, '15, p. 557 

 ("type" examined). 



Pleurobcma obliquum ruhrum (Raf.), Ortmann, '18, p. 550. 



Ohl. rubra Raf. = Q. pyramidata (Lea), Walker, 'i8c, p. 169 ("if 

 identifiable"). 



Ohliquaria rubra Raf. is not identifiable from the original 

 description. Only the red nacre speaks for this, but hardly 

 any other character ; in fact, several of the latter contradict it. 

 The beaks are said to be little prominent, and the comparison 

 with EUiptio and Obliquaria ellipsaria, could not possibly be 

 understood, if this is pyramidatus. 



Pleurohcma mytiloides Raf., which has been taken for pyra- 

 mida^tus, is the U. clava Lam. (which see) on account of the 

 distinct rays in figure and description. 



Ohliquaria triangularis Raf. '20, p. 309, is not this, because 

 of the statement that there is no longitudinal depression on 

 the disk. The same is true of Ohliquaria sintoxia Raf., '20, 

 p. 310 (moreover, the so-called Poulson "type" of the latter 

 has been identified by Vanatta as Ftisconaia subrotunda (Lea) 

 (which see). It is also true of Ohovari-a pachostea Raf., p. 

 312 {^ Amhlema antrosa Raf., p. 322), which has a rounded 

 shell. Of Ohliquaria lateralis Raf., p. 310, it has been shown 

 that it is Pleurohema cordatum (Raf.) (which see). 



The oldest valid name, therefore, is U. pyramidatus Lea. 



PIvEurO'BEma cIvAva (Lamarck), 1819 

 Type locality: Incorrectly given as Lake Erie. 



Unio clava Lamarck, '19, p. 74. 



Unio elliptica Rafinesque, '20, p. 296. 



Obliquaria scalenia Rafinesque, '20, p. 309, pi. 81, f. 24-25. 



Pleurobcma mytiloides Rafinesque, '20, p. 313, pi. 82, f. 8-9-10. 



Pleurobema cuneata Rafinesque, '20, p. 313. 



Unio patulus Lea, '29, p. 331, pi. 12, f. 20. 



Uii. clava Lam. = [/. scalenia Raf., Lea, '34, p. 89 (type examined). 



