UPEER TENNESSEE DRAINAGE. 585 
74. LAMPSILIS ORBICULATA (Hildreth), 1828. 
Unio orbiculatus Hildreth, ’28.—Lampsilis orbiculata Ortmann, 7120, 
p. 343 (anatomy ).—Lampsilis orbiculata Simpson, ’14, p. 76. 
Not reported previously from the upper Tennessee region, but 
in the Walker collection are two specimens labeled ‘‘ Holston R., 
Tenn.,” which come from the Lewis collection (and thus probably 
are from the Tennessee). 1 have found myself two specimens in the 
Clinch, one at Offutt, Anderson Co., the other at Solway, Knox Co., 
Tenn. 
This species is also in the Tennessee in North Alabama, at the 
mussel shoals near Florence (reported by Hinkley, and represented 
in Walker coll. and Carnegie Mus.). 
Type locality: Muskingum River, Marietta, Ohio. 
Genus: TRUNCILLA Rafinesque (1820). 
Ortmann, 120, p. 354. 
The subgenera distinguished by Simpson require revision, also 
with regard to nomenclature. I disregard them for the present, re- 
marking only that the soft parts furnish good criteria for their defi- 
nition. 
75. TRUNCILLA TRIQUETRA Rafinesque, 1820. 
Truncilla triqueter Rafinesque, ’20.—Unio triangularis Lewis, ’71.— 
Unio triangularis Pilsbry & Rhoads, ’96—Truncilla triquetra 
Ortmann, '12), p. 355 (anatomy ).—Tvruncilla triquetra Simpson, 
Ape 5. 
Rather frequent both in larger and smaller rivers, but nowhere 
in great numbers. Tennessee below Knoxville (Lewis) and at 
Knoxville (Pilsbry & Rhoads) ; Little River in Knox Co. (Walker 
coll.) ; lower Nolichucky; Holston River up to the South Fork at 
Pactolus, Sullivan Co., Tenn., and the North Fork at Mendota, 
Washington Co., Va.; in the Clinch up to Clinchport, Scott Co., Va.; 
in the Powell, up to Shawanee, Claiborne Co., Tenn. 
Type locality: Falls of the Ohio. 
PROC, AMER. PHIL. SOC., VOL. LVII, MM, OCT, I, 1918. 
