UPPER TENNESSEE DRAINAGE. 569 
Genus: NEPHRONAIAS Fischer & Crosse (1893).* 
Ortmann, ’12), p. 324. 
54. NEPHRONAIAS LIGAMENTINA GIBBA (Simpson), 1900. 
Unio ligamentinus Lewis, ’71—Unio ligamentinus Pilsbry & Rhoads, 
’°96. —Nephronaias ligamentina (incl. gibba) Ortmann, 7120, 
(anatomy ).—Nephronatas ligamentina gibba Goodrich, ’13, Pp. 
94.—Lampsilis ligamentina gibba Simpson, ’14, p. 82. 
The main species is not represented in the upper Tennessee 
region, although occasional specimens turn up, which are hard to dis- 
tinguish from it. The var. gibba is extremely abundant in all the 
larger rivers: Powell, Clinch, Holston, French Broad, Tennessee, but 
in the upstream direction it disappears before it reaches the head- 
waters region. In the Powell, it has been observed up to Shawanee, 
Claiborne Co., Tenn.; in the Clinch, up to St. Paul, Wise Co., Va.; 
in the North Fork Holston, up to Holston Bridge, Scott Co., Va.; 
in the South Fork, up to Pactolus, Sullivan Co., Tenn. From the 
French Broad it also enters the lower part of the Nolichucky, at 
Chunn’s Shoals, Hamblen Co., Tenn. 
Type locality: “Ohio River and southward.” 
55. NEPHRONAIAS PECTOROSA (Conrad), 1834. 
Unio pectorosus Conrad, May, ’34.—Unio perdix Lea, August, ’34. 
—Unio biangularis Lea, ’40—Unio biangulatus Lea, ’43.—Unio 
biangulatus Lewis, ’71—Umio biangularis Pilsbry & Rhoads, ’96. 
—Nephronmas perdix Ortmann, ’12b, p. 3260 (anatomy).— 
Nephronatas perdix Ortmann, ’13), p. 311.—Nephronaias perdix 
Goodrich, ’13, p. 94—Lampsilis biangularis and perdix Simpson, 
"14, pp. 59 and 88. 
The date of publication of U. perdix Lea is incorrectly given by 
Simpson as 1827. There is no question that biangularis and perdix 
are the same species, and it is quite astonishing that this identity has 
not been recognized by Simpson. Recently, Frierson has suggested 
to me that vittatis Rafinesque, 1831, from Greene River, Ky., might 
1 Possibly the generic name should be changed to Actinonaias; compare 
Frierson, Nautilus, 31, 1917, p. 48. 
PROC. AMER. PHIL. SOC., VOL. LVII, LL, OCT. I, 1918. 
