570 ORTMANN—NAYADES OF 
be this species. However, I hesitate to accept this, till it has been 
shown that this species actually exists in Greene River. 
N. pectorosa is found in the Tennessee below and at Knoxville 
(Lewis, Pilsbry & Rhoads), but it seems to be rare there. Farther 
up, it goes into Clinch, Powell, Holston, French Broad, and lower 
Nolichucky, and it is also in Little River. It ascends toward the 
headwaters farther than does N. ligamentina gibba, and goes, in the 
Powell, to Pennington Gap, Lee Co., Va.; in the Clinch to Cleve- 
land, Russell Co., Va.; in North Fork Holston, to Saltville; Smyth 
Co., Va.; in South Fork Holston, to Barron, Washington Co., Va.; 
and in the Watauga, to Watauga, Carter Co., Tenn. Just in the 
region, where N. ligamentina gibba begins to disappear (north of 
the Va.-Tenn. state line), N. pectorosa is most abundant and in its 
best development. 
Type locality: Elk River, North Alabama. 
Genus: AMYGDALONAIAS Fischer & Crosse (1893). 
Ortmann, 120; p. 327. 
56. AMYGDALONAIAS TRUNCATA ‘(Rafinesque), 1820. 
Truncilla truncata Rafinesque, ’20.—Unio elegans Lewis, ’71.— 
Amygdalonaias elegans Ortmann, ’12b, p. 328 (anatomy ).— 
Plagiola (Amygdalonaias) elegans Simpson, 14, p. 307.— 
Plagiola elegans Vanatta, ’15, p. 553.—Amygdalonaias truncata 
Utterback, ’16, p. 148. 
Vanatta does not accept Rafinesque’s specific name on account of 
Unio truncata Spengler, 1793. However, these do not conflict 
(Walker, ’16). 
Not abundant, and missing in the headwaters. Tennessee below 
Knoxville (Lewis) ; Clinch River, Solway, Knox Co.; Edgemoor 
and Clinton, Anderson Co.; Black Fox Ford, Union Co.; Clinch 
River Station, Claiborne Co.; Oakman, Grainger Co., Tenn. Hol- 
ston River, McBee Ford, near Hodges, Jefferson Co., Tenn. 
Type locality: Ohio River (type from Falls of the Ohio, accord- 
ing to Vanatta). 
