Occasional Papers of the Museum of Zoology 19 



designated O. sitbrohmda as the type of this genus, which 

 makes Rotnndaria the same as Obovaria as used by Simpson 

 (type, U. retusa Lam., congeneric with O. suhrdtunda Raf.). 

 See Obovaria. No other name being available for the present 

 genus, Dr. Pilsbry has suggested that of "Cyclonaias," which 

 we adopt here with the type given above. 



PlETHobasus cyphyus (Rafinesque), 1820 

 Type locality: Falls of the Ohio at Louisville, Ky. 



Obliquaria cyphya Rafinesque, '20, p. 305. 



Unio asopus Green, '27, p. 46, f. 3. 



Unio cyphia Rai.^zU. cesopus Green = t/. cicatricostts Say, '29 = 

 U. varicosus Lea, '29, Conrad, '34, p. 68. 



U. cyphia Raf. := U. cesopiis Green, Ferussac, '35, p. 27. 



U. cyphyus Raf., Call, '00, p. 496. 



Pleurobcma cyphia (Raf.) =F/. cesopus (Green), Vanatta, '15, p. 

 556 ("type"' examinel). 



Obi. cyphya Rai.^Pleur. crsopus (Green), Walker, '18°, p. 181 ("if 

 identifiable"). 



Plethobasus cyphyus (Raf.), Ortmann, '19, p. 65. 



The chestnut-brown color of the epidermis, the flexuous 

 border of the shell, the thick oblique rib of the disk with a few 

 tubercles, characters given in the original description, undoubt- 

 edly indicate this species, as maintained by Call. Thus the 

 name cyphya (not to be spelled cyphia) stands. 



Lexingtonia dolabElloides (Lea), 1840 



Type locality: Holston River, Tennessee. 



Unio dolabelloides Lea, '40, p. 288. 



Pleurobcma dolabelloides (Lea), Simpson, '14, p. 752. 



Lexingtonia dolabelloides (Lea), Ortmann, '18, p. 545. 



Lexingtonia conradi (Vanatta), 191 5 



Type locality: {niaculatits Conrad) Elk and Flint rivers, 

 tributaries of Tennessee in Alabama. 



Unio maculatus Conrad, '34, p. 30, pl. 4, f- 4 (not Unio nigra 

 maculata Raf., '20). 



