UPPER TENNESSEE DRAINAGE. 567 



Genus: Obovaria Rafinesque (1820). 

 Ortmann, J2b, p. 320. 



51. Obovaria (Obovaria) retusa (Lamarck), 1819. 



Unio retusa Lamarck, '19. — Obovaria retusa Ortmann, '12&, p. 321 



(anatomy). — Obovaria (Obovaria) retusa Simpson, '14, p. 290. 



Reported by Call from the Holston River in east Tennessee, but 

 missing in Lewis's list. There are specimens in the Carnegie Mu- 

 seum (from the Smith collection) labeled: Tennessee River, Knox 

 Co., Tenn. ; and others in the Walker collection labeled : Holston 

 River, Knox Co., and Holston River, Knoxville, Tenn. In all these 

 cases, apparently, the Tennessee River at and below Knoxville is 

 meant. I found this species only once : a young specimen in Clinch 

 River, at Clinton, Anderson Co., Tenn. 



In the Walker collection are also specimens from the Tennessee 

 at Bridgeport, Jackson Co., Ala., and from Florence, Lauderdale Co., 

 Ala. (also reported by Hinkley). 



Thus this species seems to belong to the upper Tennessee fauna, 

 going up to Knoxville and into the lower Clinch; but it apparently is 

 very rare. 



Some of my specimens of 0. sitbrofunda from the Holston 

 (Mascot) have slighly incurved beaks and purple nacre, and resemble 

 0. retusa to a dergee. Already Wilson and Clark ('14) have indi- 

 cated a similar approaching of the two species in Cumberland River. 



Type locality: ? (Nova Scotia per errorem). 



52. Obovaria (Obovaria) subrotunda (Rafinesque), 1820. 



Obliquaria subrotunda Rafinesque, '20. — Unio cir cuius Lewis, '71. — 

 Unio cir cuius Pilsbry & Rhoads, '96. — Obovaria cir cuius Ort- 

 mann, '12b (anatomy). — Obovaria {Obovaria) circulus Simpson, 

 '14, p. 291. — Obovaria subrotunda Vanatta, '15, p. 552. 

 The identity of Obliquaria subrotunda and Obovaria striata 



Rafinesque with U . circulus Lea has been recognized by Conrad in 



1834, who selected subrotunda as name, which thus must be used. 

 Apparently rare in the upper Tennessee region. Reported from 



the Tennessee below Knoxville (Lewis), and at Knoxville (Call, 



