Occasional Papers of the Museum of Zoology 25 
Quadrula pyramidata (lea), Simpson, 14, p. 888. 
Quad, rubra (Raf.) =Q. byramidata (Lea), Vanatta, 715, p. 557 
(“type”’ examined). 
Pleurobema obliquum rubrum (Raf.), Ortmann, ’18, p. 550. 
Obl. rubra Raf. =Q. pyramidata (Lea), Walker, ’18¢, p. 169 (“if 
identifiable’). 
Obliquaria 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 Elliptio and Obliquaria ellipsaria could not possibly be 
understood, if this is pyramidatus. 
Pleurobema mytiloides Raf., which has been taken for pyra- 
midatus, is the U. clava Lam. (which see) on account of the 
distinct rays in figure and description. 
Obliquaria 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 Obliquaria sintoxvia Raf., ’20, 
p. 310 (moreover, the so-called Poulson “type” of the latter 
has been identified by Vanatta as Fusconaia subrotunda (Lea) 
(which see). It is also true of Obovaria pachostea Raf., p. 
312 (= Amblema antrosa Raf., p. 322), which has a rounded 
shell. Of Obliquaria lateralis Raf., p. 310, it has been shown 
that it is Pleurobema cordatum (Raf.) (which see). 
The oldest valid name, therefore, is U. pyramidatus Lea. 
PLEUROBEMA CLAVA (Lamarck), 1819 
Tv pe locality: Incorrectly given as Lake Erie. 
Unio clava Lamarck, 19, p. 74. 
Unio elliptica Rafinesque, ’20, p. 206. 
Obliquaria scalenia Rafinesque, ’20, p. 309, pl. 81, f. 24-25. 
Pleurobema mytiloides Rafinesque, ’20, p. 313, pl. 82, f. 8-9-10. 
Pleurobema cuneata Rafinesque, ’20, p. 313. 
Unio patulus Lea, ’29, p. 331, pl. 12, f. 20. 
Un, clava Lam. =U. scalenia Raf., Lea, ’34, p. 89 (type examined). 
