ORTMANN: monograph of the naiades of PENNSYLVANIA. 301 



exactly as elsewhere. In the Cumberland, it goes up to the falls (and a little 

 beyond), according to Wilson & Clark (1914); and it has been reported from the 

 Tennessee River as far up as the Holston (Lewis, 1871; Call, 1885), and here it 

 reaches southwestern Virginia, as I have ascertained, in the Clinch River. 



The distribution is thus rather restricted, being confined to the larger rivers 

 of the Ohio system. Outside of Pennsylvania I found this species in the rough 

 parts of rivers. In the Ohio below Pittsburgh, where there is more steady current 

 and finer bottom material, it is by no means so abundant as in the Allegheny, 

 for instance. The clam-diggers on the Ohio take it regularly, but not in great 

 numbers. 



I have treated as spurious a few records of this species from the lower St. 

 Lawrence in Canada and the Maumee River. 



Lampsilis ovata ventricosa (Barnes) (1823). 

 Lampsilis ventricosa (Barnes) Simpson, 1914, p. 38.'^^ 



Plate XVIII, fig. 4; Plate XIX, figs. 1, 2, 3. 



Records from Pennsylvania: 



Harn, 1891 (western Pennsylvania) (as U. occidens and U. subovatus). 



Stiipakoff, 1894 (Allegheny Co.) (as U. cariosus). 



Marshall, 1895 (Allegheny River, Warren Co.) (as U. occidens). 



Rhoads, 1899 (specimens from Ohio River, Coraopolis, Allegheny Co., and from Beaver River, Wampum, 



LawTence Co., recorded as U. ovatus, belong here). 

 Ortmann, 19096, p. 182, 202. 



Characters of the shell: Shell large, often very large, rather thin when j'oung, 

 but attaining considerable thickness when old. Outline subelliptical or subovate, 

 rather short and high, hardly ever one-and-a-half times as long as high, mostly 

 much shorter. Anterior margin rounded. Lower margin curved. Upper margin 

 short, nearly straight, passing in a blunt angle or gentle curve into the obliquely 

 descending posterior margin. Posterior and lower margins meeting in a blunt, 

 rounded posterior point. Beaks more or less swollen, moderately elevated, located 

 anterior to the middle of the shell. Beak-sculpture consisting of four or five rather 

 coarse bars, of which the second and third have a slight tendency to fall into two 

 loops, with a light sinus in the middle, while the first is indistinct, and the fourth 



"'According to Vanatta (1915, p. 551), Lampsilis cardiiim Rafincsque (1820) is this. I do not 

 accept this identification, since the original description of Rafinesque clearly shows that L. cardium is 

 the female of L. ovata (Say). 



The figures of Unio cariosus given by DeKay (1843, PI. 21, figs. 243, 244), quoted also by Simpson 

 (1914, p. 44) under L. cariosa, are undoubtedly L. ovata ventricosa, and not cariosa. 



